Foldable light-emitting device having trapezoid spacer

ABSTRACT

A highly portable and highly browsable light-emitting device is provided. A light-emitting device that is less likely to be broken is provided. The light-emitting device has a strip-like region having high flexibility and a strip-like region having low flexibility that are arranged alternately. In the region having high flexibility, a light-emitting panel and a plurality of spacers overlap with each other. In the region having low flexibility, the light-emitting panel and a support overlap with each other. When the region having high flexibility is bent, the angle between normals of facing planes of the two adjacent spacers changes according to the bending of the light-emitting panel; thus, a neutral plane can be formed in the light-emitting panel or in the vicinity of the light-emitting panel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/095,943, filed Nov. 12, 2020, now pending, which is a continuation ofU.S. application Ser. No. 16/248,890, filed Jan. 16, 2019, now U.S. Pat.No. 10,840,464, which is a continuation of U.S. application Ser. No.15/807,670, filed Nov. 9, 2017, now U.S. Pat. No. 10,199,585, which is acontinuation of U.S. application Ser. No. 14/921,059, filed Oct. 23,2015, now U.S. Pat. No. 9,818,961, which claims the benefit of a foreignpriority application filed in Japan as Serial No. 2014-219135 on Oct.28, 2014, all of which are incorporated by reference.

TECHNICAL FIELD

One embodiment of the present invention relates to a light-emittingdevice. In particular, one embodiment of the present invention relatesto a light-emitting device utilizing organic electroluminescence(hereinafter also referred to as EL).

Note that one embodiment of the present invention is not limited to theabove technical field. Examples of the technical field of one embodimentof the present invention include a semiconductor device, a displaydevice, a light-emitting device, a power storage device, a memorydevice, an electronic device, a lighting device, an input device (e.g.,a touch sensor), an input/output device (e.g., a touch panel), a drivingmethod thereof, and a manufacturing method thereof.

BACKGROUND ART

Recent light-emitting devices and display devices are expected to beapplied to a variety of uses and become diversified.

For example, light-emitting devices and display devices for mobiledevices and the like are required to be thin, lightweight, and lesslikely to be broken.

Light-emitting elements utilizing EL (also referred to as EL elements)have features such as ease of thinning and lightening, high-speedresponse to input signal, and driving with a direct-current low voltagesource; therefore, application of the light-emitting elements tolight-emitting devices and display devices has been proposed.

For example, Patent Document 1 discloses a flexible active matrixlight-emitting device in which an organic EL element and a transistorserving as a switching element are provided over a film substrate.

REFERENCE Patent Document

[Patent Document 1] Japanese Published Patent Application No.2003-174153

DISCLOSURE OF INVENTION

For application to mobile devices, the size of a light-emitting deviceor display device has been reduced so that the device can be highlyportable. On the other hand, a larger light-emitting region or displayregion has been required so that the device can be highly browsable.

An object of one embodiment of the present invention is to provide ahighly portable light-emitting device, display device, input/outputdevice, electronic device, or lighting device. Another object of oneembodiment of the present invention is to provide a highly browsablelight-emitting device, display device, input/output device, orelectronic device. Another object of one embodiment of the presentinvention is to provide a highly portable and highly browsablelight-emitting device, display device, input/output device, orelectronic device.

Another object of one embodiment of the present invention is to providea novel light-emitting device, display device, input/output device,electronic device, or lighting device. Another object of one embodimentof the present invention is to provide a light-emitting device, displaydevice, input/output device, electronic device, or lighting device thatis less likely to be broken. Another object of one embodiment of thepresent invention is to provide a highly reliable light-emitting device,display device, input/output device, electronic device, or lightingdevice. Another object of one embodiment of the present invention is toprovide a light-emitting device, display device, input/output device,electronic device, or lighting device with low power consumption.

Another object of one embodiment of the present invention is to providea lightweight light-emitting device or the like. Another object of oneembodiment of the present invention is to provide a thin light-emittingdevice or the like. Another object of one embodiment of the presentinvention is to provide a flexible light-emitting device or the like.Another object of one embodiment of the present invention is to providea light-emitting device or lighting device with a seamless largelight-emitting region or a display device, input/output device, orelectronic device with a seamless large display region.

Note that the descriptions of these objects do not disturb the existenceof other objects. In one embodiment of the present invention, there isno need to achieve all the objects. Other objects can be derived fromthe description of the specification, the drawings, and the claims.

One embodiment of the present invention is a light-emitting deviceincluding a first region, a second region, and a third region. The firstregion is positioned between the second region and the third region. Thefirst region has higher flexibility than the second region and the thirdregion. The first region includes a light-emitting panel and a pluralityof spacers. The second region includes the light-emitting panel and afirst support. The third region includes the light-emitting panel and asecond support. The light-emitting panel has higher flexibility than thefirst support and the second support. The first region includes aportion where each of the plurality of spacers and the light-emittingpanel overlap with each other. The second region includes a portionwhere the first support and the light-emitting panel overlap with eachother. The third region includes a portion where the second support andthe light-emitting panel overlap with each other. When the first regionis bent, the angle between normals of facing planes of the two adjacentspacers changes according to the bending of the light-emitting panel.

Another embodiment of the present invention is a light-emitting deviceincluding a first region, a second region, and a third region. The firstregion is positioned between the second region and the third region. Thefirst region has higher flexibility than the second region and the thirdregion. The first region includes a light-emitting panel and a pluralityof spacers. The second region includes the light-emitting panel and afirst support. The third region includes the light-emitting panel and asecond support. The light-emitting panel has higher flexibility than thefirst support and the second support. The first region includes aportion where each of the plurality of spacers and the light-emittingpanel overlap with each other. The second region includes a portionwhere the first support and the light-emitting panel overlap with eachother. The third region includes a portion where the second support andthe light-emitting panel overlap with each other. The plurality ofspacers each include a portion fixed to the light-emitting panel.

Another embodiment of the present invention is a light-emitting deviceincluding a first region, a second region, and a third region. The firstregion is positioned between the second region and the third region. Thefirst region has higher flexibility than the second region and the thirdregion. The first region includes a light-emitting panel, a protectivelayer, and a plurality of spacers. The second region includes thelight-emitting panel, the protective layer, and a first support. Thethird region includes the light-emitting panel, the protective layer,and a second support. The light-emitting panel has higher flexibilitythan the first support and the second support. The protective layer hashigher flexibility than the first support and the second support. Thefirst region includes a portion where each of the plurality of spacersand the light-emitting panel overlap with each other with the protectivelayer positioned therebetween. The second region includes a portionwhere the first support and the light-emitting panel overlap with eachother with the protective layer positioned therebetween. The thirdregion includes a portion where the second support and thelight-emitting panel overlap with each other with the protective layerpositioned therebetween. The plurality of spacers each include a portionfixed to the protective layer.

In one embodiment of the present invention, the number of the spacers istwo or more. For example, one embodiment of the present invention is alight-emitting device including a first region, a second region, and athird region. The first region is positioned between the second regionand the third region. The first region has higher flexibility than thesecond region and the third region. The first region includes alight-emitting panel, a first spacer, and a second spacer. The secondregion includes the light-emitting panel and a first support. The thirdregion includes the light-emitting panel and a second support. Thelight-emitting panel has higher flexibility than the first support andthe second support. The first region includes a portion where the firstspacer and the light-emitting panel overlap with each other. The firstregion includes a portion where the second spacer and the light-emittingpanel overlap with each other. The second region includes a portionwhere the first support and the light-emitting panel overlap with eachother. The third region includes a portion where the second support andthe light-emitting panel overlap with each other. When the first regionis bent, the angle between normals of facing planes of the first spacerand the second spacer changes according to the bending of thelight-emitting panel.

Another embodiment of the present invention is a light-emitting deviceincluding a first region, a second region, and a third region. The firstregion is positioned between the second region and the third region. Thefirst region has higher flexibility than the second region and the thirdregion. The first region includes a light-emitting panel, a firstspacer, and a second spacer. The second region includes thelight-emitting panel and a first support. The third region includes thelight-emitting panel and a second support. The light-emitting panel hashigher flexibility than the first support and the second support. Thefirst region includes a portion where the first spacer and thelight-emitting panel overlap with each other. The first region includesa portion where the second spacer and the light-emitting panel overlapwith each other. The second region includes a portion where the firstsupport and the light-emitting panel overlap with each other. The thirdregion includes a portion where the second support and thelight-emitting panel overlap with each other. The first spacer includesa portion fixed to the light-emitting panel. The second spacer includesa portion fixed to the light-emitting panel.

Another embodiment of the present invention is a light-emitting deviceincluding a first region, a second region, and a third region. The firstregion is positioned between the second region and the third region. Thefirst region has higher flexibility than the second region and the thirdregion. The first region includes a light-emitting panel, a protectivelayer, a first spacer, and a second spacer. The second region includesthe light-emitting panel, the protective layer, and a first support. Thethird region includes the light-emitting panel, the protective layer,and a second support. The light-emitting panel has higher flexibilitythan the first support and the second support. The protective layer hashigher flexibility than the first support and the second support. Thefirst region includes a portion where the first spacer and thelight-emitting panel overlap with each other with the protective layerpositioned therebetween. The first region includes a portion where thesecond spacer and the light-emitting panel overlap with each other withthe protective layer positioned therebetween. The second region includesa portion where the first support and the light-emitting panel overlapwith each other with the protective layer positioned therebetween. Thethird region includes a portion where the second support and thelight-emitting panel overlap with each other with the protective layerpositioned therebetween. The first spacer includes a portion fixed tothe protective layer. The second spacer includes a portion fixed to theprotective layer.

In the above structure, the protective layer preferably includes aportion fixed to the light-emitting panel. In particular, in the firstregion, the protective layer preferably includes a portion fixed to thelight-emitting panel.

Another embodiment of the present invention is a light-emitting deviceincluding a first region, a second region, and a third region. The firstregion is positioned between the second region and the third region. Thefirst region has higher flexibility than the second region and the thirdregion. The first region includes a light-emitting panel and aconnection portion. The second region includes the light-emitting paneland a first support. The third region includes the light-emitting paneland a second support. The light-emitting panel has higher flexibilitythan the first support and the second support. The first region includesa portion where the connection portion and the light-emitting paneloverlap with each other. The second region includes a portion where thefirst support and the light-emitting panel overlap with each other. Thethird region includes a portion where the second support and thelight-emitting panel overlap with each other. The connection portionincludes an elastic body and a plurality of spacers. The elastic body isconfigured to connect the first support and the second support. Theplurality of spacers each include an opening. The plurality of spacersare connected to each other through the elastic body in the openings.

Another embodiment of the present invention is a light-emitting deviceincluding a first region, a second region, and a third region. The firstregion is positioned between the second region and the third region. Thefirst region has higher flexibility than the second region and the thirdregion. The first region includes a light-emitting panel and aconnection portion. The second region includes the light-emitting paneland a first support. The third region includes the light-emitting paneland a second support. The light-emitting panel has higher flexibilitythan the first support and the second support. The first region includesa portion where the connection portion and the light-emitting paneloverlap with each other. The second region includes a portion where thefirst support and the light-emitting panel overlap with each other. Thethird region includes a portion where the second support and thelight-emitting panel overlap with each other. The connection portion isconfigured to connect the first support and the second support. Theconnection portion includes an elastic body, a first spacer, and asecond spacer. The first spacer includes an opening. The second spacerincludes an opening. The first spacer and the second spacer areconnected to each other through the elastic body in the openings.

In the above structure, the plurality of spacers each preferably includea portion fixed to the light-emitting panel.

In any of the above structures, the elastic body is preferably a springor rubber.

In any of the above structures, the length of the elastic body ispreferably a natural length or longer in a state where thelight-emitting device is opened. Note that the natural length here meansthe length of the elastic body (such as a spring or rubber) to which noload is applied (i.e., the length of the elastic body not expanding orcontracting).

In any of the above structures, a protective layer is preferably furtherincluded. The first region includes a portion where the connectionportion and the light-emitting panel overlap with each other with theprotective layer positioned therebetween. The second region includes aportion where the first support and the light-emitting panel overlapwith each other with the protective layer positioned therebetween. Thethird region includes a portion where the second support and thelight-emitting panel overlap with each other with the protective layerpositioned therebetween.

In any of the above structures, in the first region, the plurality ofspacers each preferably include a portion fixed to the protective layer.

In any of the above structures, in the first region, the protectivelayer preferably includes a portion fixed to the light-emitting panel.

In any of the above structures, the width of a first surface of thespacer on the light-emitting panel side is larger than the width of asecond surface of the spacer on the side opposite to the light-emittingpanel side.

In the above, the light-emitting device including the light-emittingpanel is described as an example; however, a display device or aninput/output device to which any of the above structures is applied isalso one embodiment of the present invention. A display device of oneembodiment of the present invention includes a display panel. Aninput/output device of one embodiment of the present invention includesa touch panel.

One embodiment of the present invention is a module including alight-emitting device, a display device, or an input/output device towhich any of the above structures is applied. The module is providedwith a connector such as a flexible printed circuit (FPC) or a tapecarrier package (TCP) or is mounted with an IC by a chip on glass (COG)method or the like.

An electronic device or a lighting device including the above module isalso one embodiment of the present invention. For example, oneembodiment of the present invention is an electronic device includingthe above module and at least one of an antenna, a battery, a housing, aspeaker, a microphone, an operation switch, and an operation button.

According to one embodiment of the present invention, a highly portablelight-emitting device, display device, input/output device, electronicdevice, or lighting device can be provided. According to one embodimentof the present invention, a highly browsable light-emitting device,display device, input/output device, or electronic device can beprovided. According to one embodiment of the present invention, a highlyportable and highly browsable light-emitting device, display device,input/output device, or electronic device can be provided.

According to one embodiment of the present invention, a novellight-emitting device, display device, input/output device, electronicdevice, or lighting device can be provided. According to one embodimentof the present invention, a light-emitting device, display device,input/output device, electronic device, or lighting device that is lesslikely to be broken can be provided. According to one embodiment of thepresent invention, a highly reliable light-emitting device, displaydevice, input/output device, electronic device, or lighting device canbe provided. According to one embodiment of the present invention, alight-emitting device, display device, input/output device, electronicdevice, or lighting device with low power consumption can be provided.

According to one embodiment of the present invention, a lightweightlight-emitting device or the like can be provided. According to oneembodiment of the present invention, a thin light-emitting device or thelike can be provided. According to one embodiment of the presentinvention, a flexible light-emitting device or the like can be provided.According to one embodiment of the present invention, a light-emittingdevice or lighting device with a seamless large light-emitting region ora display device, input/output device, or electronic device with aseamless large display region can be provided.

Note that the description of these effects does not disturb theexistence of other effects. One embodiment of the present invention doesnot necessarily achieve all the effects listed above. Other effects canbe derived from the description of the specification, the drawings, andthe claims.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C illustrate an example of a light-emitting device.

FIGS. 2A to 2C illustrate an example of a light-emitting device.

FIGS. 3A to 3C illustrate an example of a light-emitting device.

FIGS. 4A and 4B illustrate examples of a connection portion and aspacer.

FIG. 5 illustrates an example of a connection portion.

FIGS. 6A and 6B each illustrate an example of a light-emitting device.

FIGS. 7A to 7C illustrate examples of a light-emitting device.

FIGS. 8A to 8C illustrate an example of a light-emitting device.

FIGS. 9A to 9C illustrate an example of a light-emitting device.

FIGS. 10A to 10C illustrate an example of a light-emitting device.

FIGS. 11A to 11C illustrate an example of a light-emitting device.

FIGS. 12A to 12C illustrate examples of a light-emitting device.

FIGS. 13A to 13C illustrate examples of a light-emitting device.

FIGS. 14A and 14B illustrate an example of a light-emitting panel.

FIGS. 15A and 15B illustrate an example of a light-emitting panel.

FIGS. 16A to 16D illustrate examples of a light-emitting panel.

FIGS. 17A and 17B illustrate examples of a light-emitting panel.

FIGS. 18A to 18C illustrate an example of a touch panel.

FIGS. 19A and 19B illustrate an example of a touch panel.

FIGS. 20A and 20B each illustrate an example of a touch panel.

FIGS. 21A to 21C illustrate examples of a touch panel.

FIGS. 22A to 22C are photographs of a light-emitting device in Example.

FIGS. 23A to 23C are photographs of a light-emitting device in Example.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments will be described in detail with reference to theaccompanying drawings. Note that the present invention is not limited tothe description below, and it is easily understood by those skilled inthe art that various changes and modifications can be made withoutdeparting from the spirit and scope of the present invention. Therefore,the present invention should not be construed as being limited to thedescription in the following embodiments.

Note that in the structures of the invention described below, the sameportions or portions having similar functions are denoted by the samereference numerals in different drawings, and description of suchportions is not repeated. Further, the same hatching pattern is appliedto portions having similar functions, and the portions are notespecially denoted by reference numerals in some cases.

The position, size, range, or the like of each structure illustrated indrawings is not accurately represented in some cases for easyunderstanding. Therefore, the disclosed invention is not necessarilylimited to the position, size, range, or the like disclosed in thedrawings.

Note that the terms “film” and “layer” can be interchanged with eachother depending on the case or circumstances. For example, the term“conductive film” can be used instead of the term “conductive layer,”and the term “insulating layer” can be used instead of the term“insulating film.”

Embodiment 1

In this embodiment, a light-emitting device of one embodiment of thepresent invention will be described with reference to FIGS. 1A to 1C,FIGS. 2A to 2C, FIGS. 3A to 3C, FIGS. 4A and 4B, FIG. 5, FIGS. 6A and6B, FIGS. 7A to 7C, FIGS. 8A to 8C, FIGS. 9A to 9C, FIGS. 10A to 10C,FIGS. 11A to 11C, FIGS. 12A to 12C, and FIGS. 13A to 13C.

Although a light-emitting device mainly including an organic EL elementis described in this embodiment as an example, one embodiment of thepresent invention is not limited to this example. A light-emittingdevice or a display device including another light-emitting element ordisplay element which will be described in Embodiment 2 as an example isalso one embodiment of the present invention. Moreover, one embodimentof the present invention is not limited to the light-emitting device orthe display device and can be applied to a variety of devices such as aninput/output device.

A light-emitting device of one embodiment of the present inventionincludes a strip-like region with high flexibility and a strip-likeregion with low flexibility that are arranged alternately. Thelight-emitting device can be folded by bending the region with highflexibility. The light-emitting device of one embodiment of the presentinvention is highly portable in a folded state, and is highly browsablein an opened state because of a seamless large light-emitting region.

In the light-emitting device of one embodiment of the present invention,the region with high flexibility can be bent inwardly or outwardly. Inthe light-emitting device of this embodiment, one light-emitting panelcan be folded once or more times. The radius of curvature in that casecan be, for example, greater than or equal to 0.01 mm and less than orequal to 150 mm.

Note that in this specification, being “bent inwardly” means being bentsuch that a light-emitting surface of a light-emitting panel facesinward, and being “bent outwardly” means being bent such that alight-emitting surface of a light-emitting panel faces outward. Alight-emitting surface of a light-emitting panel or a light-emittingdevice refers to a surface through which light emitted from alight-emitting element is extracted.

When the light-emitting device of one embodiment of the presentinvention is not in use, it can be folded such that a light-emittingsurface of a light-emitting panel faces inward, whereby thelight-emitting surface can be prevented from being damaged orcontaminated.

When the light-emitting device of one embodiment of the presentinvention is in use, it can be opened so that the seamless largelight-emitting region is entirely used, or it can be folded such thatthe light-emitting surface of the light-emitting panel faces outward andthe light-emitting region can be partly used. Folding the light-emittingdevice and putting part of the light-emitting region that is hidden froma user in a non-light-emitting state can reduce the power consumption ofthe light-emitting device.

One embodiment of the present invention is a light-emitting devicehaving a first region, a second region, and a third region. The firstregion is positioned between the second region and the third region. Thefirst region has the highest flexibility of the first to third regions.The second region includes a light-emitting panel and a first supportwhich overlap with each other. The third region includes thelight-emitting panel and a second support which overlap with each other.Note that the light-emitting panel has higher flexibility than the firstsupport and the second support.

The first region includes the light-emitting panel and a plurality ofspacers. In the first region, the plurality of spacers each overlap withthe light-emitting panel.

In the first region that has high flexibility, the light-emitting paneland a member (here, the spacers) are positioned so as to overlap witheach other; thus, the first region can have high mechanical strength andhigh resistance to bending as compared with the case where the firstregion includes only the light-emitting panel.

However, when the light-emitting panel and the member are positioned soas to overlap with each other, a neutral plane (a plane which does notexpand or contract) in which distortion of stress, such as compressivestress or tensile stress, due to deformation such as bending might bepositioned apart from the light-emitting panel. As the neural plane isfarther from the light-emitting panel, comparative stress or tensilestress due to bending is more applied to the light-emitting panel; thus,the light-emitting panel is likely to be broken.

In view of the above, the light-emitting device of one embodiment of thepresent invention has a structure in which, when the first region isbent, the angle between normals of facing planes of the two adjacentspacers changes according to the bending of the light-emitting panel.With such a structure, the neutral plane can be prevented from beingapart from the light-emitting panel. The neutral plane is formed closeto the light-emitting panel or in the light-emitting panel, whereby thelight-emitting panel cannot easily expand or contract even when thelight-emitting device is bent. Accordingly, the light-emitting panel canbe prevented from being broken owing to the folding.

An example of a light-emitting device that has two regions having lowflexibility and one region having high flexibility between the tworegions and can be folded in two parts will be described below. In thisembodiment, a region having high flexibility and a region having lowflexibility or regions with low flexibility are parallel to each other;however, the regions are not necessarily arranged parallel to eachother.

Structure Example A

FIG. 1A illustrates a light-emitting device that is opened. FIG. 1Billustrates the light-emitting device that is being opened or beingfolded. FIG. 1C illustrates the light-emitting device that is folded.

The light-emitting device has a first region 151, a second region 152,and a third region 153. The first region 151 is positioned between thesecond region 152 and the third region 153. The first region 151 has thehighest flexibility of the three regions.

The light-emitting device includes a light-emitting panel 101, a support103(1), a support 103(2), and a plurality of spacers 108.

The light-emitting panel 101 has a light-emitting region 111 (alsoreferred to as a light-emitting portion, a pixel portion, or a displayportion) and a non-light-emitting region 112. The non-light-emittingregion 112 is provided so as to surround the light-emitting region 111.

The light-emitting panel 101 is flexible. A light-emitting panel usingorganic EL elements is particularly preferable, in which case it canhave high flexibility and impact resistance, and in addition, can bethinner and more lightweight.

The support 103(1) and the support 103(2) are apart from each other. Thetwo supports each have lower flexibility than the light-emitting panel101.

The first region 151 includes the light-emitting panel 101 and theplurality of spacers 108. The plurality of spacers 108 each overlap withthe light-emitting panel 101. The plurality of spacers 108 are eachfixed to the light-emitting panel 101. The adjacent spacers 108 are notfixed to each other. With such a structure, when the first region 151 isbent, the angle between normals of facing planes of the two adjacentspacers 108 changes according to the bending of the light-emitting panel101. Accordingly, a neutral plane can be formed in the light-emittingpanel 101 or in the vicinity of the light-emitting panel 101.

Some of the spacers 108 may be positioned in a region which does notoverlap with the light-emitting panel 101. Alternatively, all thespacers 108 may overlap with the light-emitting panel 101.

In this embodiment, the spacers 108 are positioned on the side oppositeto the light-emitting surface side of the light-emitting panel 101;however, one embodiment of the present invention is not limited thereto.For example, the spacers 108 may be positioned on the light-emittingsurface side of the light-emitting panel 101. In the case where thespacers 108 are positioned on the light-emitting surface side of thelight-emitting panel 101, the spacers 108 preferably overlap with onlythe non-light-emitting region 112. In the case where the spacers 108overlap with the light-emitting region 111, a material which transmitsvisible light is preferably used for the spacers 108.

In the second region 152, the light-emitting panel 101 and the support103(1) overlap with each other. The support 103(1) is positioned on theside opposite to the light-emitting surface side of the light-emittingpanel 101. The light-emitting panel 101 and the support 103(1) may befixed to each other.

In the third region 153, the light-emitting panel 101 and the support103(2) overlap with each other. The support 103(2) is positioned on theside opposite to the light-emitting surface side of the light-emittingpanel 101. The light-emitting panel 101 and the support 103(2) may befixed to each other.

The supports are preferably provided only on the side opposite to thelight-emitting surface side of the light-emitting panel 101 because thelight-emitting device can be thin and lightweight.

Structure Example B

FIG. 2A illustrates a light-emitting device that is opened. FIG. 2Billustrates the light-emitting device that is being opened or beingfolded. FIG. 2C illustrates the light-emitting device that is folded.Note that in the following structure examples (including modificationexamples), description of structures similar to those described in anyof the above structure examples is omitted in some cases.

The light-emitting device includes the light-emitting panel 101, asupport 103 a(1), a support 103 a(2), a support 103 b(1), a support 103b(2), and a connection portion 105.

The support 103 a(1) and the support 103 a(2) are apart from each other.The support 103 b(1) and the support 103 b(2) are apart from each other.The four supports each have lower flexibility than the light-emittingpanel 101.

In the second region 152, the light-emitting panel 101 is providedbetween the support 103 a(1) and the support 103 b(1). The support 103a(1) is positioned on the light-emitting surface side of thelight-emitting panel 101. The support 103 b(1) is positioned on the sideopposite to the light-emitting surface side of the light-emitting panel101. The light-emitting panel 101 may be fixed to at least one of thesupport 103 a(1) and the support 103 b(1).

In the third region 153, the light-emitting panel 101 is providedbetween the support 103 a(2) and the support 103 b(2). The support 103a(2) is positioned on the light-emitting surface side of thelight-emitting panel 101. The support 103 b(2) is positioned on the sideopposite to the light-emitting surface side of the light-emitting panel101. The light-emitting panel 101 may be fixed to at least one of thesupport 103 a(2) and the support 103 b(2).

The supports are preferably provided on both the light-emitting surfaceside and the side opposite to the light-emitting surface side of thelight-emitting panel 101 because the light-emitting panel 101 can besandwiched between the pair of supports and thus the mechanical strengthof a region having low flexibility can be increased. As a result, thelight-emitting device can be less likely to be broken.

The first region 151 includes the light-emitting panel 101 and theconnection portion 105. The light-emitting panel 101 and the connectionportion 105 overlap with each other.

FIGS. 3A to 3C are side views of the connection portion 105 in thestates shown in FIGS. 2A to 2C, respectively. FIG. 4A and FIG. 5 areeach an example of a top view of the connection portion 105. FIG. 4B isa perspective view of the spacer 108.

The connection portion 105 includes an elastic body 106 and theplurality of spacers 108.

In FIGS. 3A to 3C, FIG. 4A, and FIG. 5, the elastic body 106 is shownwith a thin solid line; however, in an actual structure, the elasticbody 106 is not exposed on the outside of the spacers 108 but positionedin openings provided in the spacers 108.

One end portion of the elastic body 106 is fixed to the support 103b(1), and the other end portion of the elastic body 106 is fixed to thesupport 103 b(2). That is, the elastic body 106 connects the support 103b(1) and the support 103 b(2).

The openings are provided in the spacers 108. The spacers 108 areconnected to each other through the elastic body 106. Specifically, theelastic body 106 connects the plurality of spacers 108 through theopenings. There is no particular limitation on the number of theopenings in the spacers 108.

There is no particular limitation on the number of the spacers 108.

The number of the spacers 108 in the light-emitting device may be one.In the case where one spacer 108 is provided in the light-emittingdevice, the angle between normals of facing planes of the spacer 108 andthe support needs to change according to the bending of thelight-emitting panel. With such a structure, the neutral plane can beprevented from being apart from the light-emitting panel.

The number of the spacers 108 in the light-emitting device is preferablytwo or more.

In the example of FIG. 4A, 10 spacers 108 are arranged in one direction.In the example of FIG. 5, there are two lines in each of which 10spacers 108 are arranged in one direction, and the connection portion105 includes 20 spacers 108 in total.

The number of the spacers 108 arranged in one line is preferably largerbecause the light-emitting device can be bent more smoothly.Furthermore, the width (the length in the short-side direction) of eachof the spacers 108 is preferably narrower because the light-emittingdevice can be bent more smoothly. The light-emitting device can havehigh resistance to bending when a large number of spacers 108 eachhaving a small width are arranged.

In the structure of FIG. 5, the spacers 108 are arranged in two lines,and there is a space between the two lines. On the other hand, in thestructure of FIG. 4A, the spacers 108 are arranged in one line, and thusthere is no space. Therefore, a bent portion of the light-emitting panelis less likely to be exposed when the light-emitting device is folded;thus, the light-emitting panel can be prevented from being damaged andelements in the light-emitting panel can be prevented from being broken.

The plurality of spacers 108 each overlap with the light-emitting panel101. The plurality of spacers 108 are connected to each other throughthe elastic body 106 in the openings, but are not fixed to each other.With such a structure, when the first region 151 is bent, the anglebetween normals of facing planes of the two adjacent spacers 108 changesaccording to the bending of the light-emitting panel 101. Accordingly, aneutral plane can be formed in the light-emitting panel 101 or in thevicinity of the light-emitting panel 101.

An enlarged view of two adjacent spacers 108 is shown in the upper rightportion of FIG. 3C. In FIG. 3C, an angle θ between the normals of thefacing planes of the two adjacent spacers 108 is an acute angle. As thelight-emitting device is opened from the state of FIG. 3C, the angle θbecomes smaller. When the angle θ becomes 0° in the state of FIG. 3A,that is, when the facing planes of the two adjacent spacers 108 are incontact with each other, the light-emitting device cannot be furtherbent. That is, the first region 151 in this case can be regarded as aportion that cannot be outwardly bent.

In this example, the spacers 108 are positioned on the side opposite tothe light-emitting surface side of the light-emitting panel 101 and thefirst region 151 can be inwardly bent but cannot be outwardly bent;however, one embodiment of the present invention is not limited thereto.In the case where the spacers 108 are positioned on the light-emittingsurface side of the light-emitting panel 101, the first region 151 canbe outwardly bent but cannot be inwardly bent.

It is possible to bend the light-emitting device illustrated in FIG. 3Cwith a radius of curvature smaller than that shown in FIG. 3C. However,there is a possibility that the light-emitting panel 101 is broken whenthe light-emitting panel 101 is bent with too small a radius ofcurvature. In order to prevent that, the support 103 b(1) and thesupport 103 b(2) are preferably kept at a certain distance from eachother by adjusting the thicknesses of the support 103 a(1) and thesupport 103 a(2) or providing a fixing unit for fixing the two supportsto each other, for example. In this case, the light-emitting panel 101can be prevented from being bent with too small a radius of curvature.

The range in which the light-emitting device can be bent at the firstregion 151 can be controlled by adjusting the shapes or the number ofthe spacers 108.

For example, there is no particular limitation on the cross-sectionalshape of the spacer 108 along the direction perpendicular to thelongitudinal direction, and it may be a circle or a polygon (including apolygon with rounded corners) such as a triangle, a quadrangle, apentagon, or a hexagon.

For example, as described in this Structure Example B, as thecross-sectional shape of the spacer 108 along the directionperpendicular to the longitudinal direction, a shape in which two facingside surfaces of the spacer 108 (two surfaces facing the respectiveadjacent spacers 108) are parallel to each other, such as a square, arectangle, or a parallelogram, can be used. In this case, a regionhaving high flexibility can be either inwardly or outwardly bent.

Alternatively, for example, as described below in Structure Example D,the cross-sectional shape of the spacer 108 along the directionperpendicular to the longitudinal direction can be a shape in which twofacing side surfaces of the spacer 108 are not parallel to each other,such as a trapezoid. In this case, a region having high flexibility canbe inwardly and outwardly bent.

The plurality of spacers 108 are each preferably fixed to thelight-emitting panel 101 because the spacers 108 can be prevented frombeing moved in the longitudinal direction of the spacers 108.

For the elastic body 106, a spring or rubber can be used, for example.In the light-emitting device that is opened, the length of the elasticbody 106 is preferably a natural length or longer. In this case, thelight-emitting device can be easily kept opened. On the other hand, inorder to easily keep the light-emitting device folded, the length of theelastic body 106 is made shorter than the natural length when thelight-emitting device is opened.

Modification Example 1

FIGS. 6A and 6B are each a top view of a light-emitting device that isopened.

In the case of the light-emitting device illustrated in FIG. 6A, boththe light-emitting region 111 and the non-light-emitting region 112 areseen by a user viewing a light-emitting surface of the light-emittingdevice.

In the case of the light-emitting device illustrated in FIG. 6B, thenon-light-emitting region 112 is not seen and only the light-emittingregion 111 is seen by a user viewing a light-emitting surface of thelight-emitting device.

The light-emitting device illustrated in FIG. 6A is a modificationexample of Structure Example B, but may be applied to Structure ExampleA. Similarly, the light-emitting device illustrated in FIG. 6B is amodification example of Structure Example A, but may be applied toStructure Example B.

In the light-emitting devices illustrated in FIGS. 6A and 6B, alight-blocking layer 109 is provided. The light-blocking layer 109overlaps with the connection portion 105 or the spacers 108. Since thelight-blocking layer 109 is positioned so as to overlap with theconnection portion 105 or the spacers 108, the connection portion 105 orthe spacers 108 can be prevented from being seen by a user viewing thelight-emitting surface of the light-emitting device.

The light-blocking layer 109 may overlap with the non-light-emittingregion 112 of the light-emitting panel. When the light-blocking layer109 is positioned so as to overlap with the non-light-emitting region112, the non-light-emitting region 112 can be prevented from beingirradiated with external light. Accordingly, photodegradation of atransistor and the like of a driver circuit that is included in thenon-light-emitting region 112 can be prevented.

For the light-blocking layer 109, a flexible material that can blocklight is used. For example, resin, plastic, metal, alloy, rubber, paper,or the like can be used. A film or a tape formed using any of them maybe used. Note that a bonding layer may be provided between thelight-blocking layer 109 and the connection portion 105.

Modification Example 2

FIG. 7A is a top view of a light-emitting device that is opened. FIG. 7Bis a side view of the light-emitting device that is folded.

The light-emitting device illustrated in FIGS. 7A and 7B includes onespacer 108. In the spacer 108, a plurality of cuts are provided. Aplurality of projections separated by the cuts function like theplurality of spacers described in the above structure examples. That is,when the first region 151 is bent, the angle between normals of facingplanes of the two adjacent projections changes according to the bendingof the light-emitting panel 101. Accordingly, a neutral plane can beformed in the light-emitting panel 101 or in the vicinity of thelight-emitting panel 101. The cuts are preferably formed deeply becausea neutral plane can be easily formed in the light-emitting panel 101 orin the vicinity of the light-emitting panel 101. Note that two or morespacers 108 each having a cut may be provided.

The light-emitting device illustrated in FIGS. 7A and 7B includes afixing unit 107. With the fixing unit 107, the light-emitting panel 101can be prevented from being bent with too small a radius of curvaturewhen the light-emitting device is folded, and thus the light-emittingdevice can be prevented from being broken. As the fixing unit 107, amagnet-type or mechanical-type fixing unit can be used. The fixing unit107 can keep the light-emitting device folded.

Modification Example 3

FIG. 7C is a side view of a light-emitting device that is opened. Thelight-emitting device illustrated in FIG. 7C is a modification exampleof the light-emitting device illustrated in FIGS. 3A to 3C.

A protective layer 113 a may be provided on a light-emitting surface ofthe light-emitting panel 101. In the case where the protective layer 113a transmits visible light, the protective layer 113 a can be positionedso as to overlap with the light-emitting region 111. In the case wherethe protective layer 113 a does not transmit visible light, theprotective layer 113 a has an opening in a portion overlapping with thelight-emitting region 111. The protective layer 113 a may also serve asthe light-blocking layer 109.

A protective layer 113 b may be provided between the light-emittingpanel 101 and the connection portion 105. The protective layer 113 b isfixed to the connection portion 105. For example, the plurality ofspacers 108 are each fixed to the protective layer 113 b, in which casethe spacers 108 can be prevented from being moved in the longitudinaldirection of the spacers 108.

The protective layer 113 b is also preferably fixed to thelight-emitting panel 101. In particular, in a region where thelight-emitting panel 101, the protective layer 113 b, and the connectionportion 105 overlap with one another, the protective layer 113 b ispreferably fixed to the light-emitting panel 101. In that case, themechanical strength of the first region 151 with high flexibility can befurther increased.

The protective layer 113 b is preferably thinner because a neutral planeis less likely to be apart from the light-emitting panel 101 and thelight-emitting panel 101 can be prevented from being broken. Theprotective layer 113 b is positioned on the side opposite to thelight-emitting surface side of the light-emitting panel 101, and thusthe protective layer 113 b does not necessarily transmit visible light.The protective layer 113 b is preferably thicker because the mechanicalstrength of the light-emitting device can be increased and thus thelight-emitting panel 101 can be effectively protected. The thickness ofthe protective layer 113 b can be, for example, 0.01 to 10 times,preferably 0.05 to 5 times, more preferably 0.05 to 3 times as large asthe thickness of the light-emitting panel 101.

The protective layer 113 b can be positioned so as to overlap with boththe light-emitting region 111 and the non-light-emitting region 112. Aregion where the protective layer 113 b and the light-emitting panel 101overlap with each other preferably has a larger area because thelight-emitting panel 101 can be more effectively protected and thereliability of the light-emitting device can be improved. For example,the protective layer 113 b is positioned so as to overlap with at leastone of (preferably, each of) the support 103 a(1), the support 103 a(2),the support 103 b(1), and the support 103 b(2).

The protective layers preferably have higher flexibility than thesupports. Furthermore, the protective layers are preferably thinner thanthe supports.

When at least one of the protective layer 113 a and the protective layer113 b is provided, a region with high flexibility can also have highmechanical strength; thus, the light-emitting device can be less likelyto be broken. This structure makes the light-emitting device less likelyto be broken by deformation due to external force or the like in theregion with high flexibility as well as a region with low flexibility.

In the case where one of the protective layer 113 a and the protectivelayer 113 b is provided, the light-emitting device can be thinner andmore lightweight.

In the case where both the protective layer 113 a and the protectivelayer 113 b are provided, the light-emitting panel can be sandwichedbetween the pair of protective layers and thus the mechanical strengthof the light-emitting device can be increased; as a result, thelight-emitting device can be less likely to be broken.

<Examples of Materials for Light-Emitting Device>

There is no particular limitation on materials for the spacer, theprotective layer, and the support; they can each be formed usingplastic, metal, alloy, rubber, or the like, for example. Plastic,rubber, or the like is preferably used because it can form a spacer, aprotective layer, or a housing that is lightweight and less likely to bebroken. For example, silicone rubber may be used for the protectivelayer and stainless steel or aluminum may be used for the spacer and thesupport.

The spacer, the protective layer, and the support are each preferablyformed using a material with high toughness. In that case, alight-emitting device with high impact resistance that is less likely tobe broken can be provided. For example, when an organic resin, a thinmetal material, or a thin alloy material is used for the spacer, theprotective layer, and the support, the light-emitting device can belightweight and less likely to be broken. For a similar reason, also asubstrate of the light-emitting panel is preferably formed using amaterial with high toughness.

The spacer, the protective layer, and the support on the light-emittingsurface side do not necessarily have a light-transmitting property ifthey do not overlap with the light-emitting region of the light-emittingpanel. When the spacer, the protective layer, and the support on thelight-emitting surface side overlap with at least part of thelight-emitting region, they are preferably formed using a material thattransmits light emitted from the light-emitting panel. There is nolimitation on the light-transmitting property of the spacer, theprotective layer, and the support on the side opposite to thelight-emitting surface side.

When any two of the spacer, the protective layer, the support, and thelight-emitting panel are bonded to each other, any of a variety ofadhesives can be used, and for example, a curable resin that is curableat room temperature (e.g., a two-component-mixture-type resin), a lightcurable resin, a heat curable resin, or the like can be used.Alternatively, a sheet-like adhesive may be used. Alternatively,components of the light-emitting device may be fixed with, for example,a screw that penetrates two or more of the spacer, the protective layer,the support, and the light-emitting panel or a pin or clip that holdsthem.

The light-emitting device of one embodiment of the present invention canbe used with one light-emitting panel (one light-emitting region)divided into two or more regions at a folded portion(s). For example, itis possible to put the region that is hidden by folding thelight-emitting device in a non-light-emitting state and put only theexposed region in a light-emitting state. Thus, power consumed by aregion that is not used by a user can be reduced.

The light-emitting device of one embodiment of the present invention mayinclude a sensor for determining whether each region with highflexibility is bent or not. The sensor can be composed of, for example,a switch such as a magnetic switch or a pressure sensor such as a MEMSpressure sensor.

A light-emitting device that includes two regions with high flexibilityand three regions with low flexibility and can be folded in three partsis described below as an example. In this embodiment, an example inwhich one of the two regions with high flexibility is bent inwardly andthe other is bent outwardly is described; however, one embodiment of thepresent invention is not limited thereto. That is, when a light-emittingdevice having a plurality of regions with high flexibility is folded, alight-emitting panel is not necessarily bent inwardly and outwardlyalternately. All the plurality of regions with high flexibility may bebent either inwardly or outwardly. Furthermore, the plurality of regionswith high flexibility may be bent inwardly plural times and outwardlyplural times.

Structure Example C

FIG. 8A illustrates a light-emitting device that is opened. FIG. 8Billustrates the light-emitting device that is being opened or beingfolded. FIG. 8C illustrates the light-emitting device that is folded.

The light-emitting device has a first region 161, a second region 162, athird region 163, a fourth region 164, and a fifth region 165. The firstregion 161 is positioned between the second region 162 and the thirdregion 163. The first region 161 has the highest flexibility of thefirst to third regions. The fourth region 164 is positioned between thethird region 163 and the fifth region 165. The fourth region 164 has thehighest flexibility of the third to fifth regions.

The light-emitting device includes the light-emitting panel 101, thesupport 103(1), the support 103(2), a support 103(3), a connectionportion 105 a, and a connection portion 105 b.

The light-emitting panel 101 has the light-emitting region 111 and thenon-light-emitting region 112. The non-light-emitting region 112 isprovided so as to surround the light-emitting region 111.

The support 103(1) and the support 103(2) are apart from each other. Thesupport 103(2) and the support 103(3) are apart from each other. Thethree supports each have lower flexibility than the light-emitting panel101.

The first region 161 includes the light-emitting panel 101 and theconnection portion 105 a. The light-emitting panel 101 and theconnection portion 105 a overlap with each other.

The fourth region 164 includes the light-emitting panel 101 and theconnection portion 105 b. The light-emitting panel 101 and theconnection portion 105 b overlap with each other.

The first region 161 is a portion at which the light-emitting panel 101can be bent outwardly. The details of the connection portion 105 a willbe described later in Structure Example D.

The fourth region 164 is a portion at which the light-emitting panel 101can be bent inwardly. For the details of the connection portion 105 b,the description of the connection portion 105 in Structure Example B canbe referred to.

In the second region 162, the light-emitting panel 101 and the support103(1) overlap with each other. The support 103(1) is positioned on theside opposite to the light-emitting surface side of the light-emittingpanel 101. The light-emitting panel 101 and the support 103(1) may befixed to each other.

In the third region 163, the light-emitting panel 101 and the support103(2) overlap with each other. The support 103(2) is positioned on theside opposite to the light-emitting surface side of the light-emittingpanel 101. The light-emitting panel 101 and the support 103(2) may befixed to each other.

In the fifth region 165, the light-emitting panel 101 and the support103(3) overlap with each other. The support 103(3) is positioned on theside opposite to the light-emitting surface side of the light-emittingpanel 101. The light-emitting panel 101 and the support 103(3) may befixed to each other.

The supports are preferably provided only on the side opposite to thelight-emitting surface side of the light-emitting panel 101 because thelight-emitting device can be thin and lightweight.

Structure Example D

FIG. 9A illustrates a light-emitting device that is opened. FIG. 9Billustrates the light-emitting device that is being opened or beingfolded. FIG. 9C illustrates the light-emitting device that is folded.

The light-emitting device includes the light-emitting panel 101, thesupport 103 a(1), the support 103 a(2), a support 103 a(3), the support103 b(1), the support 103 b(2), a support 103 b(3), the connectionportion 105 a, and the connection portion 105 b.

The support 103 a(1) and the support 103 a(2) are apart from each other.The support 103 a(2) and the support 103 a(3) are apart from each other.The support 103 b(1) and the support 103 b(2) are apart from each other.The support 103 b(2) and the support 103 b(3) are apart from each other.The six supports each have lower flexibility than the light-emittingpanel 101.

The first region 161 includes the light-emitting panel 101 and theconnection portion 105 a. The light-emitting panel 101 and theconnection portion 105 a overlap with each other.

The fourth region 164 includes the light-emitting panel 101 and theconnection portion 105 b. The light-emitting panel 101 and theconnection portion 105 b overlap with each other.

In the second region 162, the light-emitting panel 101 is providedbetween the support 103 a(1) and the support 103 b(1). The support 103a(1) is positioned on the light-emitting surface side of thelight-emitting panel 101. The support 103 b(1) is positioned on the sideopposite to the light-emitting surface side of the light-emitting panel101. The light-emitting panel 101 may be fixed to at least one of thesupport 103 a(1) and the support 103 b(1).

In the third region 163, the light-emitting panel 101 is providedbetween the support 103 a(2) and the support 103 b(2). The support 103a(2) is positioned on the light-emitting surface side of thelight-emitting panel 101. The support 103 b(2) is positioned on the sideopposite to the light-emitting surface side of the light-emitting panel101. The light-emitting panel 101 may be fixed to at least one of thesupport 103 a(2) and the support 103 b(2).

In the fifth region 165, the light-emitting panel 101 is providedbetween the support 103 a(3) and the support 103 b(3). The support 103a(3) is positioned on the light-emitting surface side of thelight-emitting panel 101. The support 103 b(3) is positioned on the sideopposite to the light-emitting surface side of the light-emitting panel101. The light-emitting panel 101 may be fixed to at least one of thesupport 103 a(3) and the support 103 b(3).

The supports are preferably provided on both the light-emitting surfaceside and the side opposite to the light-emitting surface side of thelight-emitting panel 101 because the light-emitting panel 101 can besandwiched between the pair of supports and thus the mechanical strengthof a region having low flexibility can be increased. As a result, thelight-emitting device can be less likely to be broken.

FIGS. 10A to 10C are side views of the connection portion 105 a in thestates shown in FIGS. 9A to 9C, respectively.

The connection portion 105 a includes the elastic body 106 and theplurality of spacers 108. In Structure Example D, a cross-sectionalshape of the spacer 108 along the direction perpendicular to thelongitudinal direction of the spacer 108 is a trapezoid. In this case,in the first region 161, a region with high flexibility can be bentinwardly and outwardly.

In FIGS. 10A to 10C, the elastic body 106 is shown with a thin solidline; however, in an actual structure, the elastic body 106 is notexposed on the outside of the spacers 108 but positioned in openingsprovided in the spacers 108.

One end portion of the elastic body 106 is fixed to the support 103b(1), and the other end portion of the elastic body 106 is fixed to thesupport 103 b(2). That is, the elastic body 106 connects the support 103b(1) and the support 103 b(2).

The openings are provided in the spacers 108. The elastic body 106connects the plurality of spacers 108 through the openings.

The plurality of spacers 108 each overlap with the light-emitting panel101. The plurality of spacers 108 are connected to each other throughthe elastic body 106 in the openings, but are not fixed to each other.With such a structure, when the first region 161 is bent, the anglebetween normals of facing planes of the two adjacent spacers 108 changesaccording to the bending of the light-emitting panel 101. Accordingly, aneutral plane can be formed in the light-emitting panel 101 or in thevicinity of the light-emitting panel 101.

An enlarged view of two adjacent spacers 108 is shown in the lower leftportion of FIG. 10A. In FIG. 10A, an angle θ between the normals of thefacing planes of the two adjacent spacers 108 is an acute angle. As thelight-emitting device is bent from the state of FIG. 10A, the angle θbecomes smaller. When the angle θ becomes 0° in the state of FIG. 10C,the light-emitting device cannot be further bent. That is, depending onthe shape or the number of the spacers 108, the light-emitting panel 101can be prevented from being bent with too small a radius of curvaturewhen the light-emitting device is folded at the first region 161.

The light-emitting device can also be bent inwardly at the first region161 because the angle θ can be larger than in the state of FIG. 10A.

The width or the area of the surface of the spacer 108 on thelight-emitting panel 101 side is preferably larger than that on theopposite side because the light-emitting panel 101 can be bent outwardlyin the light-emitting device. The shape of the side surface of thespacer 108 is, for example, a trapezoid as illustrated in FIG. 10A. Notethat corner portions of the spacer 108 may have curvature.

The plurality of spacers 108 are each preferably fixed to thelight-emitting panel 101 because the spacers 108 can be prevented frombeing moved in the longitudinal direction of the spacers 108.

Structure Example E

FIG. 11A illustrates a light-emitting device that is opened. FIG. 11Billustrates the light-emitting device that is being opened or beingfolded. FIG. 11C illustrates the light-emitting device that is folded.FIG. 12A is a side view of the light-emitting device in the state shownin FIG. 11C. FIG. 12B is a top view of the light-emitting device in thestate shown in FIG. 11A.

As illustrated in FIG. 11A, FIG. 12B, and the like, the support 103 a(1)may overlap with the connection portion 105 a or the spacers 108. Atthis time, the support 103 a(1) is preferably formed using a materialthat blocks visible light in order that the connection portion 105 a orthe spacers 108 can be prevented from being seen by a user viewing thelight-emitting surface of the light-emitting device. Note that alight-blocking layer may be provided as described in ModificationExample 1.

In the structure where the support 103 a(1) and the support 103 a(2) arein contact with each other when the light-emitting device is opened asillustrated in FIG. 11A, FIG. 12B, and the like, the first region 161cannot be bent inwardly. In this manner, the direction in which a regionwith high flexibility is bent in the light-emitting device can becontrolled by the structure of the support.

Furthermore, as illustrated in FIG. 12A, it is preferable that a pair ofregions with low flexibility positioned on the outer side among theregions with low flexibility that overlap with one another when thelight-emitting device is folded be parallel to the support plane of thelight-emitting device, and that a region with low flexibility positionedon the inner side not be parallel to the support plane. In that case,the light-emitting device can be made thinner.

Modification Example 4

FIG. 12C is a side view of a light-emitting device that is folded. Thelight-emitting device illustrated in FIG. 12C is a modification exampleof the light-emitting device illustrated in FIG. 12A.

In the structure where the support 103 b(2) and the support 103 b(3) cankeep a certain distance from each other as illustrated in FIG. 12C byadjusting the thickness of the support 103 a(2) or the support 103 a(3),the light-emitting panel 101 can be prevented from being bent with toosmall a radius of curvature.

An example of a light-emitting device that can be folded inwardly in twoparts is described in Structure Example A, Structure Example B, and thelike; however, one embodiment of the present invention is not limitedthereto. As in Structure Example F below, a light-emitting device thatcan be folded outwardly in two parts is also one embodiment of thepresent invention.

Structure Example F

FIG. 13A illustrates a light-emitting device that is opened. FIG. 13B isa side view of the light-emitting device that is folded.

The light-emitting device has a first region 171, a second region 172,and a third region 173. The first region 171 is positioned between thesecond region 172 and the third region 173. The first region 171 has thehighest flexibility of the three regions.

The light-emitting device includes the light-emitting panel 101, thesupport 103 a(1), the support 103 a(2), the support 103 b(1), thesupport 103 b(2), and the connection portion 105.

The support 103 a(1) and the support 103 a(2) are apart from each other.The support 103 b(1) and the support 103 b(2) are apart from each other.The four supports each have lower flexibility than the light-emittingpanel 101.

The first region 171 includes the light-emitting panel 101 and theconnection portion 105. The light-emitting panel 101 and the connectionportion 105 overlap with each other.

The first region 171 is a portion at which the light-emitting panel 101can be bent outwardly. For the details, the description of theconnection portion 105 a in Structure Example D can be referred to. Thelight-emitting panel 101 may be bent inwardly at the first region 171.

In the second region 172, the light-emitting panel 101 is providedbetween the support 103 a(1) and the support 103 b(1). In the thirdregion 173, the light-emitting panel 101 is provided between the support103 a(2) and the support 103 b(2).

Modification Example 5

FIG. 13C is a side view of a light-emitting device that is folded. Thelight-emitting device illustrated in FIG. 13C is a modification exampleof the light-emitting device illustrated in FIG. 13B.

The light-emitting device illustrated in FIG. 13C includes one spacer108. In the spacer 108, a plurality of cuts are provided. A plurality ofprojections separated by the cuts function like the plurality of spacersdescribed in the above structure examples. That is, when the firstregion 171 is bent, the angle between normals of facing planes of thetwo adjacent projections changes according to the bending of thelight-emitting panel 101. Accordingly, a neutral plane can be formed inthe light-emitting panel 101 or in the vicinity of the light-emittingpanel 101. The cuts are preferably formed deeply because a neutral planecan be easily formed in the light-emitting panel 101 or in the vicinityof the light-emitting panel 101. Note that two or more spacers 108 eachhaving a cut may be provided.

As described above, in this embodiment, when a region with highflexibility in a light-emitting device has the structure in which alight-emitting panel and a member overlap with each other, themechanical strength of the region with high flexibility can be improved.A neutral plane can be formed in the light-emitting panel or in thevicinity of the light-emitting panel even when the member is provided.As a result, the light-emitting panel does not easily expand or contracteven when the light-emitting device is bent, and thus the light-emittingpanel can be prevented from being broken.

This embodiment can be combined with any of the other embodiments asappropriate.

Embodiment 2

In this embodiment, a light-emitting panel will be described withreference to drawings.

Although a light-emitting panel mainly including an organic EL elementwill be described in this embodiment as an example, one embodiment ofthe present invention is not limited to this example.

When the light-emitting panel described in this embodiment is bent, theminimum radius of curvature of a bent portion of the light-emittingpanel can be greater than or equal to 1 mm and less than or equal to 150mm, greater than or equal to 1 mm and less than or equal to 100 mm,greater than or equal to 1 mm and less than or equal to 50 mm, greaterthan or equal to 1 mm and less than or equal to 10 mm, or greater thanor equal to 2 mm and less than or equal to 5 mm. The light-emittingpanel in this embodiment is free from breakage of an element even whenbent with a small radius of curvature (e.g., greater than or equal to 2mm and less than or equal to 5 mm) and has high reliability. Bending thelight-emitting panel with a small radius of curvature can make thelight-emitting device of one embodiment of the present invention thin.There is no limitation on the direction in which the light-emittingpanel in this embodiment is bent. Further, the number of bent portionsmay be one or more than one.

Specific Example 1

FIG. 14A is a plan view of a light-emitting panel, and FIG. 14B is anexample of a cross-sectional view taken along dashed-dotted line D1-D2in FIG. 14A. The light-emitting panel in Specific Example 1 is atop-emission light-emitting panel using a color filter method. In thisembodiment, the light-emitting panel can have a structure in whichsubpixels of three colors of red (R), green (G), and blue (B), forexample, express one color; a structure in which subpixels of fourcolors of R, G, B, and white (W) express one color; a structure in whichsubpixels of four colors of R, G, B, and yellow (Y) express one color;or the like. There is no particular limitation on color elements, andcolors other than R, G, B, W, and Y may be used. For example, cyan ormagenta may be used.

The light-emitting panel illustrated in FIG. 14A includes alight-emitting portion 804, a driver circuit portion 806, and an FPC808.

The light-emitting panel illustrated in FIG. 14B includes a firstflexible substrate 701, a first bonding layer 703, a first insulatinglayer 705, a first functional layer (a plurality of transistors, aconductive layer 857, an insulating layer 815, an insulating layer 817,a plurality of light-emitting elements, and an insulating layer 821), athird bonding layer 822, a second functional layer (a coloring layer 845and a light-blocking layer 847), a second insulating layer 715, a secondbonding layer 713, and a second flexible substrate 711. The thirdbonding layer 822, the second insulating layer 715, the second bondinglayer 713, and the second flexible substrate 711 transmit visible light.Light-emitting elements and transistors in the light-emitting portion804 and the driver circuit portion 806 are sealed with the firstflexible substrate 701, the second flexible substrate 711, and the thirdbonding layer 822.

In the light-emitting portion 804, a transistor 820 and a light-emittingelement 830 are provided over the first flexible substrate 701 with thefirst bonding layer 703 and the first insulating layer 705 placedtherebetween. The light-emitting element 830 includes a lower electrode831 over the insulating layer 817, an EL layer 833 over the lowerelectrode 831, and an upper electrode 835 over the EL layer 833. Thelower electrode 831 is electrically connected to a source electrode or adrain electrode of the transistor 820. An end portion of the lowerelectrode 831 is covered with the insulating layer 821. The lowerelectrode 831 preferably reflects visible light. The upper electrode 835transmits visible light.

In the light-emitting portion 804, the coloring layer 845 overlappingwith the light-emitting element 830 and the light-blocking layer 847overlapping with the insulating layer 821 are provided. The spacebetween the light-emitting element 830 and the coloring layer 845 isfilled with the third bonding layer 822.

The insulating layer 815 has an effect of preventing diffusion ofimpurities into a semiconductor included in the transistor. As theinsulating layer 817, an insulating layer having a planarizationfunction is preferably used in order to reduce surface unevenness due tothe transistor.

In the driver circuit portion 806, a plurality of transistors areprovided over the first flexible substrate 701 with the first bondinglayer 703 and the first insulating layer 705 positioned therebetween.FIG. 14B illustrates one of the transistors included in the drivercircuit portion 806.

The first insulating layer 705 and the first flexible substrate 701 areattached to each other with the first bonding layer 703. The secondinsulating layer 715 and the second flexible substrate 711 are attachedto each other with the second bonding layer 713. The first insulatinglayer 705 and the second insulating layer 715 are preferably highlyresistant to moisture, in which case impurities such as water can beprevented from entering the light-emitting element 830 or the transistor820, leading to higher reliability of the light-emitting panel.

The conductive layer 857 is electrically connected to an external inputterminal through which a signal or a potential from the outside istransmitted to the driver circuit portion 806. Here, an example in whichthe FPC 808 is provided as the external input terminal is described. Toprevent an increase in the number of fabrication steps, the conductivelayer 857 is preferably formed using the same material and the same stepas the electrode or the wiring in the light-emitting portion or thedriver circuit portion. Here, an example is described in which theconductive layer 857 is formed using the same material and the same stepas the electrodes of the transistor 820.

In the light-emitting panel in FIG. 14B, the FPC 808 is positioned overthe second flexible substrate 711. A connector 825 is connected to theconductive layer 857 through an opening provided in the second flexiblesubstrate 711, the second bonding layer 713, the second insulating layer715, the third bonding layer 822, the insulating layer 817, and theinsulating layer 815. Furthermore, the connector 825 is connected to theFPC 808. That is, the FPC 808 and the conductive layer 857 areelectrically connected to each other through the connector 825. When theconductive layer 857 and the second flexible substrate 711 overlap witheach other, an opening formed in the second flexible substrate 711 (orthe use of a substrate with an opening) allows the conductive layer 857,the connector 825, and the FPC 808 to be electrically connected to eachother.

A modification example of the light-emitting panel illustrated in FIGS.14A and 14B will be described. FIG. 15A is a plan view of alight-emitting panel, and FIG. 15B is an example of a cross-sectionalview taken along dashed-dotted line D3-D4 in FIG. 15A. FIG. 16A is anexample of a cross-sectional view taken along dashed-dotted line D5-D6in FIG. 15A.

The light-emitting panel illustrated in FIGS. 15A and 15B shows anexample in which the first flexible substrate 701 and the secondflexible substrate 711 have different sizes. The FPC 808 is positionedover the second insulating layer 715 and does not overlap with thesecond flexible substrate 711. The connector 825 is connected to theconductive layer 857 through an opening provided in the secondinsulating layer 715, the third bonding layer 822, the insulating layer817, and the insulating layer 815. There is no limitation on thematerial for the second flexible substrate 711 because an opening doesnot need to be provided in the second flexible substrate 711.

It is preferred that the insulating layer formed using an organic resinhaving a poor gas barrier property and a poor moisture-resistantproperty not be exposed in an end portion of the light-emitting device.With such a structure, entry of impurities from the side surface of thelight-emitting device can be prevented. For example, as illustrated inFIG. 15B and FIG. 16A, the structure in which the insulating layer 817is not provided in the end portion of the light-emitting device may beemployed.

FIG. 16B shows a modification example of the light-emitting portion 804.

The light-emitting panel illustrated in FIG. 16B includes insulatinglayers 817 a and 817 b and a conductive layer 856 over the insulatinglayer 817 a. The source electrode or the drain electrode of thetransistor 820 and the lower electrode of the light-emitting element 830are electrically connected to each other through the conductive layer856.

The light-emitting panel illustrated in FIG. 16B includes a spacer 823over the insulating layer 821. The spacer 823 can adjust the distancebetween the first flexible substrate 701 and the second flexiblesubstrate 711.

The light-emitting panel in FIG. 16B includes an overcoat 849 coveringthe coloring layer 845 and the light-blocking layer 847. The spacebetween the light-emitting element 830 and the overcoat 849 is filledwith the bonding layer 822.

FIG. 16C shows a modification example of the light-emitting element 830.

Note that as illustrated in FIG. 16C, the light-emitting element 830 mayinclude an optical adjustment layer 832 between the lower electrode 831and the EL layer 833. A light-transmitting conductive material ispreferably used for the optical adjustment layer 832. Owing to thecombination of a color filter (the coloring layer) and a microcavitystructure (the optical adjustment layer), light with high color puritycan be extracted from the light-emitting panel of one embodiment of thepresent invention. The thickness of the optical adjustment layer may bevaried depending on the color of the subpixel.

Specific Example 2

A light-emitting panel illustrated in FIG. 16D includes the firstflexible substrate 701, the first bonding layer 703, the firstinsulating layer 705, a first functional layer (a conductive layer 814,a conductive layer 857 a, a conductive layer 857 b, the light-emittingelement 830, and the insulating layer 821), the second bonding layer713, and the second flexible substrate 711.

The conductive layer 857 a and the conductive layer 857 b serve asexternal connection electrodes of the light-emitting panel and can eachbe electrically connected to an FPC or the like.

The light-emitting element 830 includes the lower electrode 831, the ELlayer 833, and the upper electrode 835. An end portion of the lowerelectrode 831 is covered with the insulating layer 821. Thelight-emitting element 830 has a bottom-emission structure, atop-emission structure, or a dual-emission structure. The electrode,substrate, insulating layer, and the like through which light isextracted transmit visible light. The conductive layer 814 iselectrically connected to the lower electrode 831.

The substrate through which light is extracted may have, as a lightextraction structure, a hemispherical lens, a micro lens array, a filmprovided with an uneven surface structure, a light diffusing film, orthe like. For example, the substrate with the light extraction structurecan be formed by bonding the above lens or film to a resin substratewith an adhesive or the like having substantially the same refractiveindex as the substrate, the lens, or the film.

The conductive layer 814 is preferably, though not necessarily, providedbecause voltage drop due to the resistance of the lower electrode 831can be inhibited. In addition, for a similar purpose, a conductive layerelectrically connected to the upper electrode 835 may be provided overthe insulating layer 821, the EL layer 833, the upper electrode 835, orthe like.

The conductive layer 814 can be a single layer or a stacked layer formedusing a material selected from copper, titanium, tantalum, tungsten,molybdenum, chromium, neodymium, scandium, nickel, and aluminum, analloy material containing any of these materials as its main component,and the like. The thickness of the conductive layer 814 can be, forexample, greater than or equal to 0.1 μm and less than or equal to 3 μm,preferably greater than or equal to 0.1 μm and less than or equal to 0.5μm.

Specific Example 3

FIG. 15A is a plan view of a light-emitting panel. FIG. 17A is anexample of a cross-sectional view taken along dashed-dotted line D3-D4in FIG. 15A. The light-emitting panel in Specific Example 3 is abottom-emission light-emitting panel using a color filter method.

The light-emitting panel illustrated in FIG. 17A includes the firstflexible substrate 701, the first bonding layer 703, the firstinsulating layer 705, a first functional layer (a plurality oftransistors, the conductive layer 857, the insulating layer 815, thecoloring layer 845, the insulating layer 817 a, the insulating layer 817b, the conductive layer 856, a plurality of light-emitting elements, andthe insulating layer 821), the second bonding layer 713, and the secondflexible substrate 711. The first flexible substrate 701, the firstbonding layer 703, the first insulating layer 705, the insulating layer815, the insulating layer 817 a, and the insulating layer 817 b transmitvisible light.

In the light-emitting portion 804, the transistor 820, a transistor 824,and the light-emitting element 830 are provided over the first flexiblesubstrate 701 with the first bonding layer 703 and the first insulatinglayer 705 positioned therebetween. The light-emitting element 830includes the lower electrode 831 over the insulating layer 817 b, the ELlayer 833 over the lower electrode 831, and the upper electrode 835 overthe EL layer 833. The lower electrode 831 is electrically connected tothe source electrode or the drain electrode of the transistor 820. Anend portion of the lower electrode 831 is covered with the insulatinglayer 821. The upper electrode 835 preferably reflects visible light.The lower electrode 831 transmits visible light. There is no particularlimitation on the position of the coloring layer 845 overlapping withthe light-emitting element 830; for example, the coloring layer 845 maybe provided between the insulating layer 817 a and the insulating layer817 b or between the insulating layer 815 and the insulating layer 817a.

In the driver circuit portion 806, a plurality of transistors areprovided over the first flexible substrate 701 with the first bondinglayer 703 and the first insulating layer 705 positioned therebetween.FIG. 17A illustrates two of the transistors in the driver circuitportion 806.

The first insulating layer 705 and the first flexible substrate 701 areattached to each other with the first bonding layer 703. The firstinsulating layer 705 is preferably highly resistant to moisture, inwhich case impurities such as water can be prevented from entering thelight-emitting element 830, the transistor 820, or the transistor 824,leading to higher reliability of the light-emitting panel.

The conductive layer 857 is electrically connected to an external inputterminal through which a signal or a potential from the outside istransmitted to the driver circuit portion 806. In this example, the FPC808 is provided as the external input terminal, and the conductive layer857 is formed using the same material and the same step as theconductive layer 856.

Specific Example 4

FIG. 15A is a plan view of a light-emitting panel. FIG. 17B is anexample of a cross-sectional view taken along dashed-dotted line D3-D4in FIG. 15A. The light-emitting panel in Specific Example 4 is atop-emission light-emitting panel using a separate coloring method.

The light-emitting panel in FIG. 17B includes the first flexiblesubstrate 701, the first bonding layer 703, the first insulating layer705, a first functional layer (a plurality of transistors, theconductive layer 857, the insulating layer 815, the insulating layer817, a plurality of light-emitting elements, the insulating layer 821,and the spacer 823), the second bonding layer 713, and the secondflexible substrate 711. The second bonding layer 713 and the secondflexible substrate 711 transmit visible light.

In the light-emitting panel illustrated in FIG. 17B, the connector 825is positioned over the insulating layer 815. The connector 825 isconnected to the conductive layer 857 through an opening provided in theinsulating layer 815. The connector 825 is also connected to the FPC808. That is, the FPC 808 and the conductive layer 857 are electricallyconnected to each other through the connector 825.

Examples of Materials

Next, materials that can be used for the light-emitting panel will bedescribed. Note that description of the components already described inthis specification is omitted in some cases.

For the substrates, glass, quartz, an organic resin, a metal, an alloy,or the like can be used. The substrate through which light from thelight-emitting element is extracted is formed using a material thattransmits the light.

It is particularly preferable to use a flexible substrate. For example,it is possible to use glass, a metal, or an alloy that is thin enough tohave flexibility, or an organic resin. For example, the thickness of theflexible substrate is preferably greater than or equal to 1 μm and lessthan or equal to 200 μm, further preferably greater than or equal to 1μm and less than or equal to 100 μm, still further preferably greaterthan or equal to 1 μm and less than or equal to 50 μm, and particularlypreferably greater than or equal to 1 μm and less than or equal to 25μm.

An organic resin, which has a smaller specific gravity than glass, ispreferably used for the flexible substrate, in which case thelight-emitting panel can be lighter in weight than that using glass.

A material with high toughness is preferably used for the substrates. Inthat case, a light-emitting panel with high impact resistance that isless likely to be broken can be provided. For example, when an organicresin substrate or a metal or alloy substrate with a small thickness isused, the light-emitting panel can be lightweight and less likely to bebroken as compared with the case where a glass substrate is used.

A metal material and an alloy material, which have high thermalconductivity, are preferred because they can easily conduct heat to thewhole substrate and accordingly can prevent a local temperature rise inthe light-emitting panel. The thickness of a substrate using a metalmaterial or an alloy material is preferably greater than or equal to 10μm and less than or equal to 200 μm, further preferably greater than orequal to 20 μm and less than or equal to 50 μm.

Although there is no particular limitation on a material for the metalsubstrate and the alloy substrate, it is preferable to use, for example,aluminum, copper, nickel, or a metal alloy such as an aluminum alloy orstainless steel.

Furthermore, when a material with high thermal emissivity is used forthe substrate, the surface temperature of the light-emitting panel canbe prevented from rising, leading to prevention of breakage or adecrease in reliability of the light-emitting panel. For example, thesubstrate may have a stacked-layer structure of a metal substrate and alayer with high thermal emissivity (e.g., a layer formed using a metaloxide or a ceramic material).

Examples of a material having flexibility and a light-transmittingproperty include polyester resins such as polyethylene terephthalate(PET) and polyethylene naphthalate (PEN), a polyacrylonitrile resin, apolyimide resin, a polymethyl methacrylate resin, a polycarbonate (PC)resin, a polyethersulfone (PES) resin, a polyamide resin (e.g., nylon oraramid), a cycloolefin resin, a polystyrene resin, a polyamide imideresin, a polyvinyl chloride resin, and a polytetrafluoroethylene (PTFE)resin. In particular, a material with a low coefficient of linearexpansion is preferred, and for example, a polyamide imide resin, apolyimide resin, a polyamide resin, or PET can be suitably used. It isalso possible to use a substrate in which a fibrous body is impregnatedwith a resin (also referred to as prepreg) or a substrate whosecoefficient of linear expansion is reduced by mixing an organic resinwith an inorganic filler.

The flexible substrate may have a stacked-layer structure of a layer ofany of the above-mentioned materials and a hard coat layer by which asurface of the device is protected from damage (e.g., a silicon nitridelayer), a layer that can disperse pressure (e.g., an aramid resinlayer), or the like.

The flexible substrate may be formed by stacking a plurality of layers.When a glass layer is used, a barrier property against water and oxygencan be improved and thus a reliable light-emitting panel can beprovided.

For example, it is possible to use a flexible substrate in which a glasslayer, a bonding layer, and an organic resin layer are stacked from theside closer to a light-emitting element. The thickness of the glasslayer is greater than or equal to 20 μm and less than or equal to 200μm, preferably greater than or equal to 25 μm and less than or equal to100 μm. With such a thickness, the glass layer can have both highflexibility and a high barrier property against water and oxygen. Thethickness of the organic resin layer is greater than or equal to 10 μmand less than or equal to 200 μm, preferably greater than or equal to 20μm and less than or equal to 50 μm. Providing such an organic resinlayer outside the glass layer, occurrence of a crack or a break in theglass layer can be suppressed and mechanical strength can be improved.With the substrate using such a composite material of a glass materialand an organic resin, a flexible light-emitting panel with highreliability can be provided.

For the bonding layer, various curable adhesives such as a photo curableadhesive (e.g., an ultraviolet curable adhesive), a reactive curableadhesive, a thermosetting adhesive, and an anaerobic adhesive can beused. Examples of these adhesives include an epoxy resin, an acrylicresin, a silicone resin, a phenol resin, a polyimide resin, an imideresin, a polyvinyl chloride (PVC) resin, a polyvinyl butyral (PVB)resin, and an ethylene vinyl acetate (EVA) resin. A material with lowmoisture permeability, such as an epoxy resin, is particularlypreferred. Alternatively, a two-component resin may be used. An adhesivesheet or the like may be used.

Furthermore, the resin may include a drying agent. For example, it ispossible to use a substance that adsorbs moisture by chemicaladsorption, such as oxide of an alkaline earth metal (e.g., calciumoxide or barium oxide). Alternatively, it is possible to use a substancethat adsorbs moisture by physical adsorption, such as zeolite or silicagel. The drying agent is preferably included because it can preventimpurities such as moisture from entering the functional element,thereby improving the reliability of the light-emitting panel.

When a filler with a high refractive index or a light scattering memberis mixed into the resin, the efficiency of light extraction from thelight-emitting element can be improved. For example, titanium oxide,barium oxide, zeolite, or zirconium can be used.

Insulating films highly resistant to moisture are preferably used as thefirst insulating layer 705 and the second insulating layer 715.Alternatively, the first insulating layer 705 and the second insulatinglayer 715 preferably have a function of preventing diffusion ofimpurities to the light-emitting element.

Examples of the insulating film highly resistant to moisture include afilm containing nitrogen and silicon (e.g., a silicon nitride film and asilicon nitride oxide film) and a film containing nitrogen and aluminum(e.g., an aluminum nitride film). Alternatively, a silicon oxide film, asilicon oxynitride film, an aluminum oxide film, or the like may beused.

For example, the moisture vapor transmission rate of the insulating filmhighly resistant to moisture is lower than or equal to 1×10⁻⁵[g/(m²·day)], preferably lower than or equal to 1×10⁻⁶ [g/(m²·day)],further preferably lower than or equal to 1×10⁻⁷ [g/(m²·day)], stillfurther preferably lower than or equal to 1×10⁻⁸ [g/(m²·day)].

In the light-emitting panel, it is necessary that at least one of thefirst insulating layer 705 and the second insulating layer 715 transmitlight emitted from the light-emitting element. One of the firstinsulating layer 705 and the second insulating layer 715, whichtransmits light emitted from the light-emitting element, preferably hashigher average transmittance of light having a wavelength greater thanor equal to 400 nm and less than or equal to 800 nm than the other.

There is no particular limitation on the structure of the transistors inthe light-emitting panel. For example, a forward staggered transistor oran inverted staggered transistor may be used. A top-gate transistor or abottom-gate transistor may be used. There is no particular limitation ona semiconductor material used for the transistors, and silicon,germanium, or an organic semiconductor can be used, for example.Alternatively, an oxide semiconductor containing at least one of indium,gallium, and zinc (e.g., In—Ga—Zn-based metal oxide) may be used.

There is no particular limitation on the crystallinity of asemiconductor material used for the transistors, and an amorphoussemiconductor or a semiconductor having crystallinity (amicrocrystalline semiconductor, a polycrystalline semiconductor, asingle crystal semiconductor, or a semiconductor partly includingcrystal regions) may be used. A semiconductor having crystallinity ispreferably used, in which case deterioration of the transistorcharacteristics can be suppressed.

For stable characteristics of the transistor, a base film is preferablyprovided. The base film can be formed with a single-layer structure or astacked-layer structure using an inorganic insulating film such as asilicon oxide film, a silicon nitride film, a silicon oxynitride film,or a silicon nitride oxide film. The base film can be formed by asputtering method, a chemical vapor deposition (CVD) method (e.g., aplasma CVD method, a thermal CVD method, or a metal organic CVD (MOCVD)method), an atomic layer deposition (ALD) method, a coating method, aprinting method, or the like. Note that the base film is not necessarilyprovided if not necessary. In each of the above structure examples, thefirst insulating layer 705 can serve as a base film of the transistor.

As the light-emitting element, a self-luminous element can be used, andan element whose luminance is controlled by current or voltage isincluded in the category of the light-emitting element. For example, alight-emitting diode (LED), an organic EL element, or an inorganic ELelement can be used.

The light-emitting element can have any of a top-emission structure, abottom-emission structure, and a dual-emission structure. A conductivefilm that transmits visible light is used as the electrode through whichlight is extracted. A conductive film that reflects visible light ispreferably used as the electrode through which light is not extracted.

The conductive film that transmits visible light can be formed using,for example, indium oxide, indium tin oxide (ITO), indium zinc oxide,zinc oxide (ZnO), or zinc oxide to which gallium is added. It is alsopossible to use a film of a metal material such as gold, silver,platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron,cobalt, copper, palladium, or titanium; an alloy containing any of thesemetal materials; or a nitride of any of these metal materials (e.g.,titanium nitride) when the film is thin enough to have alight-transmitting property. Alternatively, a stack of any of the abovematerials can be used as the conductive layer. For example, a stackedfilm of ITO and an alloy of silver and magnesium is preferably used, inwhich case conductivity can be increased. Further alternatively,graphene or the like may be used.

For the conductive film that reflects visible light, a metal materialsuch as aluminum, gold, platinum, silver, nickel, tungsten, chromium,molybdenum, iron, cobalt, copper, or palladium or an alloy containingany of these metal materials can be used, for example. Lanthanum,neodymium, germanium, or the like may be added to the metal material orthe alloy. Moreover, the conductive film can be formed using an alloycontaining aluminum (an aluminum alloy) such as an alloy of aluminum andtitanium, an alloy of aluminum and nickel, an alloy of aluminum andneodymium, or an alloy of aluminum, nickel, and lanthanum (Al—Ni—La), oran alloy containing silver such as an alloy of silver and copper, analloy of silver, palladium, and copper (Ag—Pd—Cu, also referred to asAPC), or an alloy of silver and magnesium. An alloy of silver and copperis preferable because of its high heat resistance. When a metal film ora metal oxide film is stacked on an aluminum alloy film, oxidation ofthe aluminum alloy film can be suppressed. Examples of a material forthe metal film or the metal oxide film are titanium and titanium oxide.Alternatively, the conductive film having a property of transmittingvisible light and a film containing any of the above metal materials maybe stacked. For example, it is possible to use a stacked film of silverand ITO or a stacked film of an alloy of silver and magnesium and ITO.

Each of the electrodes can be formed by an evaporation method or asputtering method. Alternatively, a discharging method such as anink-jet method, a printing method such as a screen printing method, or aplating method can be used.

When a voltage higher than the threshold voltage of the light-emittingelement is applied between the lower electrode 831 and the upperelectrode 835, holes are injected to the EL layer 833 from the anodeside and electrons are injected to the EL layer 833 from the cathodeside. The injected electrons and holes are recombined in the EL layer833 and a light-emitting substance contained in the EL layer 833 emitslight.

The EL layer 833 includes at least a light-emitting layer. In additionto the light-emitting layer, the EL layer 833 may further include one ormore layers containing any of a substance with a high hole-injectionproperty, a substance with a high hole-transport property, ahole-blocking material, a substance with a high electron-transportproperty, a substance with a high electron-injection property, asubstance with a bipolar property (a substance with a highelectron-transport property and a high hole-transport property), and thelike.

For the EL layer 833, either a low molecular compound or a highmolecular compound can be used, and an inorganic compound may be used.Each of the layers included in the EL layer 833 can be formed by any ofthe following methods: an evaporation method (including a vacuumevaporation method), a transfer method, a printing method, an ink-jetmethod, a coating method, and the like.

The light-emitting element 830 may contain two or more kinds oflight-emitting substances. Thus, for example, a light-emitting elementthat emits white light can be achieved. For example, light-emittingsubstances are selected so that two or more light-emitting substancesemit complementary colors to obtain white light emission. Alight-emitting substance that emits red (R) light, green (G) light, blue(B) light, yellow (Y) light, or orange (O) light or a light-emittingsubstance that emits light containing spectral components of two or moreof R light, G light, and B light can be used, for example. Alight-emitting substance that emits blue light and a light-emittingsubstance that emits yellow light may be used, for example. At thistime, the emission spectrum of the light-emitting substance that emitsyellow light preferably contains spectral components of G light and Rlight. The emission spectrum of the light-emitting element 830preferably has two or more peaks in the visible region (e.g., greaterthan or equal to 350 nm and less than or equal to 750 nm or greater thanor equal to 400 nm and less than or equal to 800 nm).

The EL layer 833 may include a plurality of light-emitting layers. Inthe EL layer 833, the plurality of light-emitting layers may be stackedin contact with one another or may be stacked with a separation layerprovided therebetween. The separation layer may be provided between afluorescent layer and a phosphorescent layer, for example.

The separation layer can be provided, for example, to prevent energytransfer by the Dexter mechanism (particularly triplet energy transfer)from a phosphorescent material in an excited state which is generated inthe phosphorescent layer to a fluorescent material in the fluorescentlayer. The thickness of the separation layer may be several nanometers.Specifically, the thickness of the separation layer may be greater thanor equal to 0.1 nm and less than or equal to 20 nm, greater than orequal to 1 nm and less than or equal to 10 nm, or greater than or equalto 1 nm and less than or equal to 5 nm. The separation layer contains asingle material (preferably, a bipolar substance) or a plurality ofmaterials (preferably, a hole-transport material and anelectron-transport material).

The separation layer may be formed using a material contained in thelight-emitting layer in contact with the separation layer. Thisfacilitates the manufacture of the light-emitting element and reducesthe drive voltage. For example, in the case where the phosphorescentlayer contains a host material, an assist material, and thephosphorescent material (a guest material), the separation layer maycontain the host material and the assist material. In other words, theseparation layer includes a region not containing the phosphorescentmaterial and the phosphorescent layer includes a region containing thephosphorescent material in the above structure. Thus, the separationlayer and the phosphorescent layer can be separately deposited dependingon the presence of the phosphorescent material. With such a structure,the separation layer and the phosphorescent layer can be formed in thesame chamber. Thus, the manufacturing cost can be reduced.

Moreover, the light-emitting element 830 may be a single elementincluding one EL layer or a tandem element in which EL layers arestacked with a charge generation layer provided therebetween.

The light-emitting element is preferably provided between a pair ofinsulating films that are highly resistant to moisture, in which caseimpurities such as water can be prevented from entering thelight-emitting element, thereby preventing a decrease in the reliabilityof the light-emitting panel. Specifically, the use of an insulating filmhighly resistant to moisture for the first insulating layer 705 and thesecond insulating layer 715 allows the light-emitting element to belocated between a pair of insulating films highly resistant to moisture,by which a decrease in the reliability of the light-emitting panel canbe prevented.

As the insulating layer 815, an inorganic insulating film such as asilicon oxide film, a silicon oxynitride film, or an aluminum oxide filmcan be used, for example. For the insulating layers 817, 817 a, and 817b, an organic material such as polyimide, acrylic, polyamide, polyimideamide, or a benzocyclobutene-based resin can be used, for example.Alternatively, a low dielectric constant material (low-k material) orthe like can be used. Furthermore, each of the insulating layers may beformed by stacking a plurality of insulating films.

The insulating layer 821 is formed using an organic insulating materialor an inorganic insulating material. As a resin, a polyimide resin, apolyamide resin, an acrylic resin, a siloxane resin, an epoxy resin, ora phenol resin can be used, for example. It is particularly preferablethat the insulating layer 821 be formed using a photosensitive resinmaterial to have an opening portion over the lower electrode 831 so thata sidewall of the opening portion is formed as an inclined surface withcontinuous curvature.

There is no particular limitation on the method for forming theinsulating layer 821. A photolithography method, a sputtering method, anevaporation method, a droplet discharging method (e.g., an ink-jetmethod), a printing method (e.g., screen printing or off-set printing),or the like may be used.

The spacer 823 can be formed using an inorganic insulating material, anorganic insulating material, a metal material, or the like. As theinorganic insulating material and the organic insulating material, avariety of materials that can be used for the aforementioned insulatinglayers can be used, for example. As the metal material, titanium,aluminum, or the like can be used. When the spacer 823 containing aconductive material and the upper electrode 835 are electricallyconnected to each other, a potential drop due to the resistance of theupper electrode 835 can be suppressed. The spacer 823 may have a taperedshape or an inverse tapered shape.

A conductive layer functioning as an electrode of the transistor, awiring, an auxiliary wiring of the light-emitting element, or the likein the light-emitting panel can be formed with a single-layer structureor a stacked-layer structure using any of metal materials such asmolybdenum, titanium, chromium, tantalum, tungsten, aluminum, copper,neodymium, and scandium and an alloy material containing any of theseelements, for example. The conductive layer may be formed using aconductive metal oxide such as indium oxide (e.g., In₂O₃), tin oxide(e.g., SnO₂), ZnO, ITO, indium zinc oxide (e.g., In₂O₃—ZnO), or any ofthese metal oxide materials containing silicon oxide.

The coloring layer is a colored layer that transmits light in a specificwavelength range. For example, a color filter for transmitting light ina red, green, blue, or yellow wavelength range can be used. Eachcoloring layer is formed in a desired position with any of variousmaterials by a printing method, an ink-jet method, an etching methodusing a photolithography method, or the like. In a white subpixel, aresin such as a transparent resin may be provided so as to overlap withthe light-emitting element.

The light-blocking layer is provided between adjacent coloring layers.The light-blocking layer blocks light emitted from an adjacentlight-emitting element to prevent color mixture between adjacentlight-emitting elements. Here, the coloring layer is provided such thatits end portion overlaps with the light-blocking layer, whereby lightleakage can be reduced. For the light-blocking layer, a material thatblocks light from the light-emitting element can be used; for example, ablack matrix may be formed using a metal material or a resin materialcontaining pigment or dye. Note that it is preferable to provide thelight-blocking layer in a region other than the light-emitting portion,such as a driver circuit portion, in which case undesired leakage ofguided light or the like can be suppressed.

An overcoat covering the coloring layer and the light-blocking layer maybe provided. The overcoat can prevent impurities and the like containedin the coloring layer from being diffused into the light-emittingelement. The overcoat is formed with a material that transmits lightemitted from the light-emitting element; for example, it is possible touse an inorganic insulating film such as a silicon nitride film or asilicon oxide film, an organic insulating film such as an acrylic filmor a polyimide film, or a stacked layer of an organic insulating filmand an inorganic insulating film.

In the case where upper surfaces of the coloring layer and thelight-blocking layer are coated with a material of the bonding layer, amaterial that has high wettability with respect to the material of thebonding layer is preferably used as the material of the overcoat. Forexample, the overcoat is preferably an oxide conductive film such as anITO film or a metal film such as an Ag film that is thin enough totransmit light.

When the overcoat is formed using a material that has high wettabilitywith respect to the material for the bonding layer, the material for thebonding layer can be uniformly applied. Thus, entry of bubbles in thestep of attaching the pair of substrates to each other can be prevented,and thus a display defect can be prevented.

For the connector, any of a variety of anisotropic conductive films(ACF), anisotropic conductive pastes (ACP), and the like can be used.

As described above, one embodiment of the present invention can beapplied to a light-emitting panel, a display panel, a touch panel, andthe like.

Examples of a display element include a light-emitting element such asan organic EL element, an inorganic EL element, or an LED, a liquidcrystal element, an electrophoretic element, and a display element usingmicro electro mechanical systems (MEMS).

Note that the light-emitting panel of one embodiment of the presentinvention may be used as a display device or as a lighting device. Forexample, it may be used as a light source such as a backlight or a frontlight, that is, a lighting device for a display panel.

This embodiment can be combined with any of the other embodiments asappropriate.

Embodiment 3

In this embodiment, a touch panel will be described with reference todrawings. Note that the above description can be referred to for thecomponents of a touch panel, which are similar to those of thelight-emitting panel described in Embodiment 2. Although a touch panelincluding a light-emitting element is described in this embodiment as anexample, one embodiment of the present invention is not limited to thisexample. For example, a touch panel including another element (e.g., adisplay element), the example of which is shown in Embodiment 2, is alsoone embodiment of the present invention.

Structure Example 1

FIG. 18A is a top view of the touch panel. FIG. 18B is a cross-sectionalview taken along dashed-dotted line A-B and dashed-dotted line C-D inFIG. 18A. FIG. 18C is a cross-sectional view taken along dashed-dottedline E-F in FIG. 18A.

A touch panel 390 illustrated in FIG. 18A includes a display portion 301(serving also as an input portion), a scan line driver circuit 303 g(1),an imaging pixel driver circuit 303 g(2), an image signal line drivercircuit 303 s(1), and an imaging signal line driver circuit 303 s(2).

The display portion 301 includes a plurality of pixels 302 and aplurality of imaging pixels 308.

The pixel 302 includes a plurality of subpixels. Each subpixel includesa light-emitting element and a pixel circuit.

The pixel circuits can supply electric power for driving thelight-emitting element. The pixel circuits are electrically connected towirings through which selection signals are supplied. The pixel circuitsare also electrically connected to wirings through which image signalsare supplied.

The scan line driver circuit 303 g(1) can supply selection signals tothe pixels 302.

The image signal line driver circuit 303 s(1) can supply image signalsto the pixels 302.

A touch sensor can be formed using the imaging pixels 308. Specifically,the imaging pixels 308 can sense a touch of a finger or the like on thedisplay portion 301.

The imaging pixels 308 include photoelectric conversion elements andimaging pixel circuits.

The imaging pixel circuits can drive photoelectric conversion elements.The imaging pixel circuits are electrically connected to wirings throughwhich control signals are supplied. The imaging pixel circuits are alsoelectrically connected to wirings through which power supply potentialsare supplied.

Examples of the control signal include a signal for selecting an imagingpixel circuit from which a recorded imaging signal is read, a signal forinitializing an imaging pixel circuit, and a signal for determining thetime it takes for an imaging pixel circuit to sense light.

The imaging pixel driver circuit 303 g(2) can supply control signals tothe imaging pixels 308.

The imaging signal line driver circuit 303 s(2) can read out imagingsignals.

As illustrated in FIGS. 18B and 18C, the touch panel 390 includes thefirst flexible substrate 701, the first bonding layer 703, the firstinsulating layer 705, the second flexible substrate 711, the secondbonding layer 713, and the second insulating layer 715. The firstflexible substrate 701 and the second flexible substrate 711 are bondedto each other with a third bonding layer 360.

The first flexible substrate 701 and the first insulating layer 705 areattached to each other with the first bonding layer 703. The secondflexible substrate 711 and the second insulating layer 715 are attachedto each other with the second bonding layer 713. Embodiment 2 can bereferred to for materials used for the substrates, the bonding layers,and the insulating layers.

Each of the pixels 302 includes a subpixel 302R, a subpixel 302G, and asubpixel 302B (see FIG. 18C).

For example, the subpixel 302R includes a light-emitting element 350Rand the pixel circuit. The pixel circuit includes a transistor 302 tthat can supply electric power to the light-emitting element 350R.Furthermore, the subpixel 302R includes the light-emitting element 350Rand an optical element (e.g., a coloring layer 367R that transmits redlight).

The light-emitting element 350R includes a lower electrode 351R, an ELlayer 353, and an upper electrode 352, which are stacked in this order(see FIG. 18C).

The EL layer 353 includes a first EL layer 353 a, an intermediate layer354, and a second EL layer 353 b, which are stacked in this order.

Note that a microcavity structure can be provided for the light-emittingelement 350R so that light with a specific wavelength can be efficientlyextracted. Specifically, an EL layer may be provided between a film thatreflects visible light and a film that partly reflects and partlytransmits visible light, which are provided so that light with aspecific wavelength can be efficiently extracted.

The subpixel 302R includes the third bonding layer 360 that is incontact with the light-emitting element 350R and the coloring layer367R. The coloring layer 367R is positioned in a region overlapping withthe light-emitting element 350R. Accordingly, part of light emitted fromthe light-emitting element 350R passes through the third bonding layer360 and through the coloring layer 367R and is emitted to the outside ofthe subpixel 302R as indicated by an arrow in FIG. 18B or 18C.

The touch panel 390 includes a light-blocking layer 367BM. Thelight-blocking layer 367BM is provided so as to surround the coloringlayer (e.g., the coloring layer 367R).

The touch panel 390 includes an anti-reflective layer 367 p positionedin a region overlapping with the display portion 301. As theanti-reflective layer 367 p, a circular polarizing plate can be used,for example.

The touch panel 390 includes an insulating layer 321. The insulatinglayer 321 covers the transistor 302 t and the like. Note that theinsulating layer 321 can be used as a layer for planarizing unevennesscaused by the pixel circuits and the imaging pixel circuits. Aninsulating layer that can inhibit diffusion of impurities to thetransistor 302 t and the like can be used as the insulating layer 321.

The touch panel 390 includes a partition 328 that overlaps with an endportion of the lower electrode 351R. A spacer 329 that controls thedistance between the first flexible substrate 701 and the secondflexible substrate 711 is provided on the partition 328.

The image signal line driver circuit 303 s(1) includes a transistor 303t and a capacitor 303 c. Note that the driver circuit can be formed inthe same process and over the same substrate as the pixel circuits. Asillustrated in FIG. 18B, the transistor 303 t may include a second gate304 over the insulating layer 321. The second gate 304 may beelectrically connected to a gate of the transistor 303 t, or differentpotentials may be supplied to these gates. Alternatively, if necessary,the second gate 304 may be provided for the transistor 308 t, thetransistor 302 t, or the like.

The imaging pixels 308 each include a photoelectric conversion element308 p and an imaging pixel circuit. The imaging pixel circuit can senselight received by the photoelectric conversion element 308 p. Theimaging pixel circuit includes the transistor 308 t. For example, a PINphotodiode can be used as the photoelectric conversion element 308 p.

The touch panel 390 includes a wiring 311 through which a signal issupplied. The wiring 311 is provided with a terminal 319. Note that anFPC 309 through which a signal such as an image signal or asynchronization signal is supplied is electrically connected to theterminal 319. Note that a printed wiring board (PWB) may be attached tothe FPC 309.

Note that transistors such as the transistors 302 t, 303 t, and 308 tcan be formed in the same process. Alternatively, the transistors may beformed in different processes.

Structure Example 2

FIGS. 19A and 19B are perspective views of a touch panel 505. Note thatFIGS. 19A and 19B illustrate only main components for simplicity. FIGS.20A and 20B are each a cross-sectional view taken along dashed-dottedline X1-X2 in FIG. 19A.

As illustrated in FIGS. 19A and 19B, the touch panel 505 includes adisplay portion 501, the scan line driver circuit 303 g(1), a touchsensor 595, and the like. Furthermore, the touch panel 505 includes thefirst flexible substrate 701, the second flexible substrate 711, and aflexible substrate 590.

The touch panel 505 includes a plurality of pixels and a plurality ofwirings 311. The plurality of wirings 311 can supply signals to thepixels. The plurality of wirings 311 are arranged to a peripheralportion of the first flexible substrate 701, and part of the pluralityof wirings 311 form the terminal 319. The terminal 319 is electricallyconnected to an FPC 509(1).

The touch panel 505 includes the touch sensor 595 and a plurality ofwirings 598. The plurality of wirings 598 are electrically connected tothe touch sensor 595. The plurality of wirings 598 are arranged to aperipheral portion of the flexible substrate 590, and part of theplurality of wirings 598 form a terminal. The terminal is electricallyconnected to an FPC 509(2). Note that in FIG. 19B, electrodes, wirings,and the like of the touch sensor 595 provided on the back side of theflexible substrate 590 (the side facing the first flexible substrate701) are indicated by solid lines for clarity.

As the touch sensor 595, for example, a capacitive touch sensor can beused. Examples of the capacitive touch sensor are a surface capacitivetouch sensor and a projected capacitive touch sensor. An example ofusing a projected capacitive touch sensor is described here.

Examples of a projected capacitive touch sensor are a self-capacitivetouch sensor and a mutual capacitive touch sensor. The use of a mutualcapacitive type is preferable because multiple points can be sensedsimultaneously.

Note that a variety of sensors that can sense the closeness or thecontact of a sensing target such as a finger can be used as the touchsensor 595.

The projected capacitive touch sensor 595 includes electrodes 591 andelectrodes 592. The electrodes 591 are electrically connected to any ofthe plurality of wirings 598, and the electrodes 592 are electricallyconnected to any of the other wirings 598.

The electrodes 592 each have a shape of a plurality of quadranglesarranged in one direction with one corner of a quadrangle connected toone corner of another quadrangle as illustrated in FIGS. 19A and 19B.

The electrodes 591 each have a quadrangular shape and are arranged in adirection intersecting with the direction in which the electrodes 592extend. Note that the plurality of electrodes 591 are not necessarilyarranged in the direction orthogonal to one electrode 592 and may bearranged to intersect with one electrode 592 at an angle of less than 90degrees.

The wiring 594 intersects with the electrode 592. The wiring 594electrically connects two electrodes 591 between which one of theelectrodes 592 is positioned. The intersecting area of the electrode 592and the wiring 594 is preferably as small as possible. Such a structureallows a reduction in the area of a region where the electrodes are notprovided, reducing unevenness in transmittance. As a result, unevennessin luminance of light from the touch sensor 595 can be reduced.

Note that the shapes of the electrodes 591 and the electrodes 592 arenot limited to the above-mentioned shapes and can be any of a variety ofshapes.

As illustrated in FIG. 20A, the touch panel 505 includes the firstflexible substrate 701, the first bonding layer 703, the firstinsulating layer 705, the second flexible substrate 711, the secondbonding layer 713, and the second insulating layer 715. The firstflexible substrate 701 and the second flexible substrate 711 areattached to each other with the third bonding layer 360.

A bonding layer 597 attaches the flexible substrate 590 to the secondflexible substrate 711 so that the touch sensor 595 overlaps with thedisplay portion 501. The bonding layer 597 has a light-transmittingproperty.

The electrodes 591 and the electrodes 592 are formed using alight-transmitting conductive material. As a light-transmittingconductive material, a conductive oxide such as indium oxide, indium tinoxide, indium zinc oxide, zinc oxide, or zinc oxide to which gallium isadded can be used. Note that a film including graphene may be used aswell. The film including graphene can be formed, for example, byreducing a film including graphene oxide. As a reducing method, a methodwith application of heat or the like can be employed.

Note that as a material of the conductive films such as the electrodes591, the electrodes 592, and the wiring 594, that is, wirings andelectrodes forming the touch panel, a transparent conductive filmincluding indium oxide, tin oxide, zinc oxide, or the like (e.g., ITO)can be given. A low-resistance material is preferably used as a materialthat can be used as the wirings and electrodes forming the touch panel.For example, silver, copper, aluminum, a carbon nanotube, graphene, or ametal halide (such as a silver halide) may be used. Alternatively, ametal nanowire including a number of conductors with an extremely smallwidth (for example, a diameter of several nanometers) may be used.Further alternatively, a net-like metal mesh with a conductor may beused. For example, an Ag nanowire, a Cu nanowire, an Al nanowire, an Agmesh, a Cu mesh, or an Al mesh may be used. For example, in the case ofusing an Ag nanowire as the wirings and electrodes forming the touchpanel, a visible light transmittance of 89% or more and a sheetresistance of 40 ohm/square or more and 100 ohm/square or less can beachieved. Since the above-described metal nanowire, metal mesh, carbonnanotube, graphene, and the like, which are examples of the materialthat can be used as the wirings and electrodes forming the touch panel,have high visible light transmittances, they may be used as electrodesof display elements (e.g., a pixel electrode or a common electrode).

The electrodes 591 and the electrodes 592 may be formed by depositing alight-transmitting conductive material on the flexible substrate 590 bya sputtering method and then removing an unnecessary portion by any ofvarious patterning techniques such as photolithography.

The electrodes 591 and the electrodes 592 are covered with an insulatinglayer 593. Furthermore, openings reaching the electrodes 591 are formedin the insulating layer 593, and the wiring 594 electrically connectsthe adjacent electrodes 591. A light-transmitting conductive materialcan be favorably used for the wiring 594 because the aperture ratio ofthe touch panel can be increased. Moreover, a material with higherconductivity than the conductivities of the electrodes 591 and theelectrodes 592 can be favorably used for the wiring 594 because electricresistance can be reduced.

Note that an insulating layer covering the insulating layer 593 and thewiring 594 may be provided to protect the touch sensor 595.

Furthermore, a connection layer 599 electrically connects the wirings598 to the FPC 509(2).

The display portion 501 includes a plurality of pixels arranged in amatrix. Each pixel has the same structure as Structure Example 1; thus,description is omitted.

As illustrated in FIG. 20B, the touch panel may include two substratesof the first flexible substrate 701 and the second flexible substrate711 without including the flexible substrate 590. The second flexiblesubstrate 711 and the second insulating layer 715 are attached to eachother with the second bonding layer 713, and the touch sensor 595 isprovided in contact with the second insulating layer 715. The coloringlayer 367R and the light-blocking layer 367BM are provided in contactwith the insulating layer 589 that covers the touch sensor 595. Theinsulating layer 589 is not necessarily provided, in which case thecoloring layer 367R and the light-blocking layer 367BM are provided incontact with the wiring 594.

Structure Example 3

FIGS. 21A to 21C are cross-sectional views of a touch panel 505B. Thetouch panel 505B described in this embodiment is different from thetouch panel 505 in Structure Example 2 in that received image data isdisplayed on the side where the transistors are provided and that thetouch sensor is provided on the first flexible substrate 701 side of thedisplay portion. Different structures will be described in detail below,and the above description is referred to for the other similarstructures.

The coloring layer 367R is positioned in a region overlapping with thelight-emitting element 350R. The light-emitting element 350R illustratedin FIG. 21A emits light to the side where the transistor 302 t isprovided. Accordingly, part of light emitted from the light-emittingelement 350R passes through the coloring layer 367R and is emitted tothe outside of the touch panel 505B as indicated by an arrow in FIG.21A.

The touch panel 505B includes the light-blocking layer 367BM on thelight extraction side. The light-blocking layer 367BM is provided so asto surround the coloring layer (e.g., the coloring layer 367R).

The touch sensor 595 is provided not on the second flexible substrate711 side but on the first flexible substrate 701 side (see FIG. 21A).

The bonding layer 597 attaches the flexible substrate 590 to the firstflexible substrate 701 so that the touch sensor 595 overlaps with thedisplay portion. The bonding layer 597 has a light-transmittingproperty.

Note that a structure in the case of using bottom-gate transistors inthe display portion 501 is illustrated in FIGS. 21A and 21B.

For example, a semiconductor layer containing an oxide semiconductor,amorphous silicon, or the like can be used in the transistor 302 t andthe transistor 303 t illustrated in FIG. 21A.

For example, a semiconductor layer containing polycrystalline silicon orthe like can be used in the transistor 302 t and the transistor 303 tillustrated in FIG. 21B.

A structure in the case of using top-gate transistors is illustrated inFIG. 21C.

For example, a semiconductor layer containing polycrystalline silicon, asingle crystal silicon film that is transferred from a single crystalsilicon substrate, or the like can be used in the transistor 302 t andthe transistor 303 t illustrated in FIG. 21C.

This embodiment can be combined with any of the other embodiments asappropriate.

Example 1

In this example, light-emitting devices of one embodiment of the presentinvention were fabricated.

In this example, the light-emitting devices corresponding to StructureExample B (see FIG. 2A and the like) and Structure Example D (see FIG.9A and the like), respectively, were fabricated.

Light-emitting panels of this example were fabricated in the followingmanner: a separation layer (tungsten film) was formed over each of apair of formation substrates (glass substrates); layers to be separated(one of them included a transistor, a light-emitting element, and thelike, and the other included a color filter and the like) were formedover the respective separation layers; the pair of formation substrateswas separated from the layers to be separated; and then flexiblesubstrates were attached to the layers to be separated with an adhesive.

As the transistor, a transistor including a c-axis aligned crystallineoxide semiconductor (CAAC-OS) was used. Unlike amorphous semiconductor,the CAAC-OS has few defect states, so that the reliability of thetransistor can be improved. Moreover, since the CAAC-OS does not have agrain boundary, a stable and uniform film can be formed over a largearea, and stress that is caused by bending a flexible light-emittingdevice does not easily make a crack in a CAAC-OS film.

A CAAC-OS is a crystalline oxide semiconductor having c-axis alignmentof crystals in a direction substantially perpendicular to the filmsurface. It has been found that oxide semiconductors have a variety ofcrystal structures other than a single crystal structure. An example ofsuch structures is a nano-crystal (nc) structure, which is an aggregateof nanoscale microcrystals. The crystallinity of a CAAC-OS structure islower than that of a single crystal structure and higher than that of annc structure.

In this example, a channel-etched transistor including an In—Ga—Zn-basedoxide was used. The transistor was fabricated over a glass substrate ata process temperature lower than 500° C.

In a method of fabricating an element such as a transistor directly onan organic resin such as a plastic substrate, the temperature of theprocess for fabricating the element needs to be lower than the uppertemperature limit of the organic resin. In this example, the formationsubstrate is a glass substrate and the peeling layer, which is aninorganic film, has high heat resistance; thus, the transistor can befabricated at a temperature equal to that when a transistor isfabricated over a glass substrate. Thus, the performance and reliabilityof the transistor can be easily secured.

As the light-emitting element, a tandem (stacked-layer) organic ELelement emitting white light was used. The light-emitting element has atop emission structure. Light from the light-emitting element isextracted outside through a color filter.

The light-emitting panels of two kinds were fabricated.

FIGS. 22A to 22C show the light-emitting device corresponding toStructure Example B. FIG. 22A illustrates the light-emitting device thatis opened. FIG. 22B illustrates the light-emitting device that is beingopened or being folded. FIG. 22C illustrates the light-emitting devicethat is folded.

The light-emitting device illustrated in FIGS. 22A to 22C includes amagnet-type fixing unit as the fixing unit 107. The connection portion105 includes an elastic body and a plurality of spacers. Thelight-blocking layer 109 is positioned so as to overlap with theconnection portion 105, whereby the connection portion 105 can beprevented from being seen by a user viewing a light-emitting surface ofthe light-emitting device.

In the light-emitting panel of the light-emitting device illustrated inFIGS. 22A to 22C, a light-emitting portion (also referred to aslight-emitting region or pixel portion) has a size of 5.9 inchesdiagonal, 720×1280 pixels, a pixel size of 102 μm×102 μm, a resolutionof 249 ppi, and an aperture ratio of 45.2%. A built-in scan driver andan external source driver attached by chip on film (COF) were used. Theframe frequency was 60 Hz. Note that the light-emitting panel has aweight of approximately 3 g and a thickness less than 100 μm.

FIGS. 23A to 23C show the light-emitting device corresponding toStructure Example D. FIG. 23A illustrates the light-emitting device thatis opened. FIG. 23B illustrates the light-emitting device that is beingopened or being folded. FIG. 23C illustrates the light-emitting devicethat is folded.

In the light-emitting panel of the light-emitting device illustrated inFIGS. 23A to 23C, a light-emitting portion has a size of 8.7 inchesdiagonal, 1080×1920 pixels, a pixel size of 100 μm×100 μm, a resolutionof 254 ppi, and an aperture ratio of 46.0%. A built-in scan driver andan external source driver attached by COF were used. The frame frequencywas 60 Hz. Note that a capacitive touch sensor is incorporated in thelight-emitting panel. Note that the light-emitting panel has a weight ofapproximately 6 g and a thickness less than 100 μm.

As described above, by application of one embodiment of the presentinvention, a light-emitting device that is highly portable in a foldedstate and is highly browsable in an opened state because of a seamlesslarge light-emitting region was fabricated. Furthermore, alight-emitting device in which a light-emitting panel is prevented frombeing broken owing to folding was fabricated.

REFERENCE NUMERALS

101: light-emitting panel, 103: support, 103 a: support, 103 b: support,105: connection portion, 105 a: connection portion, 105 b: connectionportion, 106: elastic body, 107: fixing unit, 108: spacer, 109:light-blocking layer, 111: light-emitting region, 112:non-light-emitting region, 113 a: protective layer, 113 b: protectivelayer, 151: first region, 152: second region, 153: third region, 161:first region, 162: second region, 163: third region, 164: fourth region,165: fifth region, 171: first region, 172: second region, 173: thirdregion, 301: display portion, 302: pixel, 302B: subpixel, 302G:subpixel, 302R: subpixel, 302 t: transistor, 303 c: capacitor, 303 g(1):scan line driver circuit, 303 g(2): imaging pixel driver circuit, 303s(1): image signal line driver circuit, 303 s(2): imaging signal linedriver circuit, 303 t: transistor, 304: gate, 308: imaging pixel, 308 p:photoelectric conversion element, 308 t: transistor, 309: FPC, 311:wiring, 319: terminal, 321: insulating layer, 328: partition, 329:spacer, 350R: light-emitting element, 351R: lower electrode, 352: upperelectrode, 353: EL layer, 353 a: EL layer, 353 b: EL layer, 354:intermediate layer, 360: bonding layer, 367BM: light-blocking layer, 367p: anti-reflective layer, 367R: coloring layer, 390: touch panel, 501:display portion, 505: touch panel, 505B: touch panel, 509: FPC, 589:insulating layer, 590: flexible substrate, 591: electrode, 592:electrode, 593: insulating layer, 594: wiring, 595: touch sensor, 597:bonding layer, 598: wiring, 599: connection layer, 701: flexiblesubstrate, 703: bonding layer, 705: insulating layer, 711: flexiblesubstrate, 713: bonding layer, 715: insulating layer, 804:light-emitting portion, 806: driver circuit portion, 808: FPC, 814:conductive layer, 815: insulating layer, 817: insulating layer, 817 a:insulating layer, 817 b: insulating layer, 820: transistor, 821:insulating layer, 822: bonding layer, 823: spacer, 824: transistor, 825:connector, 830: light-emitting element, 831: lower electrode, 832:optical adjustment layer, 833: EL layer, 835: upper electrode, 845:coloring layer, 847: light-blocking layer, 849: overcoat, 856:conductive layer, 857: conductive layer, 857 a: conductive layer, and857 b: conductive layer

This application is based on Japanese Patent Application serial no.2014-219135 filed with Japan Patent Office on Oct. 28, 2014, the entirecontents of which are hereby incorporated by reference.

The invention claimed is:
 1. A light-emitting device comprising: alight-emitting panel including a light-emitting element; alight-blocking layer over the light-emitting panel; and a firsttrapezoid spacer and a second trapezoid spacer, wherein thelight-emitting device is configured to be folded in two parts, whereinthe first trapezoid spacer and the second trapezoid spacer are providedat a folded portion of the light-emitting device, wherein a side surfaceof the first trapezoid spacer is in contact with a side surface of thesecond trapezoid spacer when the light-emitting device is folded in twoparts, wherein the folded portion has a curvature radius, wherein thelight-emitting panel has a light-emitting region and anon-light-emitting region surrounding the light-emitting region, whereinthe light-blocking layer has a region overlapping the first trapezoidalspacer and the second trapezoidal spacer, and wherein thenon-light-emitting region has a region not overlapping thelight-blocking layer.
 2. The light-emitting device according to claim 1,further comprising a protective layer, wherein each of the firsttrapezoid spacer and the second trapezoid spacer has a first surfaceincluding one side of the first trapezoid spacer and the secondtrapezoid spacer, and a second surface including another side facing theone side, wherein an area of the first surface is larger than an area ofthe second surface, and wherein the first trapezoid spacer and thesecond trapezoid spacer are fixed to the protective layer at the firstsurface.
 3. The light-emitting device according to claim 2, wherein athickness of the protective layer is 0.01 to 10 times as large as athickness of the light-emitting panel.
 4. The light-emitting deviceaccording to claim 2, wherein the protective layer includes a plastic, ametal, an alloy, or a rubber.
 5. The light-emitting device according toclaim 1, wherein the curvature radius is greater than or equal to 1 mmand less than or equal to 150 mm.
 6. The light-emitting device accordingto claim 1, wherein the light-emitting panel has a neutral plane whenthe light-emitting device is changed from a folded state to an openedstate, or from an opened state to a folded state.
 7. The light-emittingdevice according to claim 6, wherein the neutral plane does not expandor contract.
 8. The light-emitting device according to claim 1, thefirst trapezoid spacer and the second trapezoid spacer include aplastic, a metal, an alloy, or a rubber.